There are currently 16 players signed up for next season, which includes midfielder Luke Summerfield, whose new deal was announced yesterday (Monday).
Millington says two deals that were close to completion last week are now on the verge of being signed off.
"They're both closer, one of them I believe the paperwork was signed this morning (Tuesday), and another one is also very close, they're just discussing final things with their agent."
Of the six others that Town were in negotiations with, Millington said: "One or two of them have moved a bit further away from us, and have got other offers they're exploring while ours is still on the table.
"There's a couple of those where we're trying to tweak things and move things around, and make it a bit more appealing to those players."
Millington says the club is in active negotiations with five players, excluding the two that are set to be announced shortly, and says the squad should be at 18 for the start of pre-season.
"We've got a centre-half who we're well down the line with, and there's another centre-half who we're in the final stages with," he said.
"He's got a few offers on the table and we're well in the conversation there, so that would put us at three centre-halves with Jesse Debrah.
"We're in the final stages with one striker. There's another one that's not a million miles behind that and we would look at potentially a third forward, someone who could play across a front three, but we've not made any significant progress with that third striker yet."
One player who won't be at The Shay next season is centre-back Pierce Bird, who has joined Fylde.
"We had some really good conversations with Pierce and King's Lynn, but he wanted more time to go and explore other avenues and we didn't really feel we could allow him that time," Millington said.
"We felt the offer that was there was right for him and for Halifax, so we had to move on, and we've done that.
"We've got another player coming in who will fill that role that we were going to give to Pierce within the squad.
"So we've moved on quickly and we've got a really exciting prospect coming in."
But one player who will be part of the squad next season is Summerfield.
"Summers is very important," said Millington, "he gives us that continuity in the middle of the park, and an element of continuity in setting the tone and the culture of the group because of the type of professional he is, and obviously his ability with the football is well known at The Shay.
"So there's any numbers of reasons you could pick to celebrate him re-signing. He's happy to stay and push us forward for another season."
Attacker Matty Warburton has been the subject of speculation regarding a move to re-join former boss Pete Wild at Barrow, but when asked if there had been any offers for him, Millington said: "Absolutely not, he's got another year with us and I don't see a set of circumstances where that would change.
"There's been interest in one or two other players but they're a fair way off progressing to the point where a player would be leaving us.
"Obviously things can change quickly in football and sometimes do, but at the moment there's not anything significant which would lead me to believe that anyone will be leaving us in the near future."
Andy Cooper was appointed as Millington's assistant manager last week, and the Town boss says Cooper will fit in well with the backroom team already in place.
"We met a number of years back on a coaching course," Millington said.
"He is also connected professionally to a member of the coaching staff, so there was working relationship there that dates back a number of years, which means we know a lot about him from day one.
"The title gives the impression of a certain set of responsibilities, but the way we operate mean it will bleed into other areas.
"Primarily he'll be looking after the coaching programme, delivering the sessions, working with the players around the style of play and the identity we want to create.
"He'll contribute input into the recruitment process, he'll have significant input into our reflective process and player support, making sure he's aware where individuals are up to and liaising and communicating with them about areas they need to be focusing on to keep moving forward and helping the team get better.
"So it's a pretty broad range of responsibilities, but I know from my own experience that it's really enjoyable and really exciting building those relationships with the payers and being part of their development and progress, not only as individuals but as footballers as well.
"He was the only one (candidate) we really had any conversations with.
"It's a difficult role to step into when there's an existing staff in place, so finding the person who could not only have a real impact from a coaching perspective - which is something I've been heavily involved with and will have to withdraw a little bit from - but also understands the processes we follow to underpin the planning, preparation, delivery and then reflection, is really crucial, so the systems and processes we have in place continue to work, and we don't have to go through a process of educating the new assistant about how we work and why.
"Also, somebody who's committed and will get behind the values of the staff because we need to be unified in our approach and the players need to know all the staff are moving in the same direction.
"So he more than ticks all those boxes and will help us drive that culture forward."
The Shaymen have announced five friendlies so far - away to Fleetwood, Mansfield, Farsley Celtic, Colne and Fylde - but Millington says there could be on further one to be played.
"There may be one other friendly announced that we're working on," he said, "just to try and manage the minutes of the players more effectively."
On why none of Town's friendlies are at home, Millington said: "We've got to make sure the pitch is given time to recover and Ozzy's given the time to do the work he needs to do to make sure that it's sustainable for as long as it can be throughout the season.
"Obviously our brand of football requires a decent surface to play on, we don't want to change the way we play, we think it's effective and we think we can be even more effective at it and more exciting, and we need the pitch to be in as good a condition as possible to do that.
"So the unfortunate reality is that we've got to try and protect it as much as we can and the only way to do that at this stage is to try and limit the number of games played on it in the short-term.
"I think it would be fantastic for us as a group and fantastic for the players if we could have a pre-season friendly or two at home this time next year or beyond, it would be a wonderful way to introduce new players to the club and introduce the fans to them.
"But obviously there are other considerations and we've got to do things that are in the long-term best interests of the team's success, and sometimes that can be taking these difficult decisions."
The Shaymen will hold pre-season fitness tests on Thursday and Friday for their current squad and triallists, overseen by physio Aaron Scholes.
"Aaron works in close partnership with Leeds Beckett University, so we get access to all their equipment and facilities," Millington explained.
"The whole process will be done down there.
"It's strength, endurance and stamina tests, a whole range of fitness tests to get base line readings for the group.
"It gives our sports science department the information they need to plan the individual fitness programmes for the players and gives us some areas to work on throughout pre-season where we can best focus our energies to make sure everyone's fully prepared for the first game of the season."
Four triallists set to be in the Town squad for the start pre-season, which Millington says is more or less already planned out.
"We know the broad brush information of what we'll be looking at in terms of training sessions from a technical and tactical perspective," he said.
"When we add the physical information into that we'll manage those sessions around the physical objectives we need to hit.
"But the plan for the schedule is all in place, we just need to fill in some of the detail into that."