Since you summoned me...
Patrick Kane (75% retained) for 1st + Olausson + C prospect, plus 3rd/prospect to Arizona/Seattle for 25% retention.
Avs get Kane for the playoffs at a $2.75m caphit, leaving loads of space for another depth D add and to cover bonuses.
The fact that MacDermid (who can play both forward and D) is the only depth guy on a one-way deal indicates that they're aiming to roll with 21 as often as possible.
With 21 they're at just over $2.5m in space, which should be more than enough to cover bonuses.
Byram would need to win a Norris, Smythe, and/or get PP1 time from Makar (if he's injured) to put up enough points to hit B bonuses which doesn't seem all that likely. But for arguments sake even if he does go off in a big way and hits some B bonuses the Avs should still be able to cover that with ~$1.5-1.8m, and cover Newhook's and Meyers' bonuses with the rest.
Newhook at 3LW probably doesn't hit all his bonuses either, and Meyers doesn't have that much anyhow, so I think they'll be alright.
There will inevitably also be injuries and perhaps someone with a big caphit going on LTIR for a few weeks would allow them to have some space for bonuses (though that would temporarily stop them from accruing for the deadline). Either way I'm pretty confident CMac will find a way as he's great at cap management.
I'd hazard a guess that they internally have ~$2m budgeted for bonuses and ~$500k for accrual, with an aim to reassess at the TDL when they have a good idea of how many bonuses guys are going to hit and how much they have accrued.
Even if cap does end up super tight at the TDL due to injuries or bonuses they'll still have plenty of options thanks to the ERod signing. For example they could trade Compher ($3.5m) in a package for Kane (75% retained/$2.675m) and actually create *more* capspace.
I really don't think Bednar has much love for MacDonald... plenty of times he should have been the guy in the lineup, but wasn't many times.
I do think 21 guys is going to be a pretty normal thing for the team though provided they stay reasonably healthy.
On the bonus side, I expect Byram will max out his A bonuses in one way or another. The combo of Meyers and Newhook are likely only to get one or two. So a millionish total. That said, if Newhook gelled right away as a 2C, not unreasonable he ends up top 6 in icetime, top 3 in +/- amongst forwards, gets 20 goals (I actually think that is a lock), and 35 assists. Meyers could pop 20g too. If all that happens, we are looking right at 1.8m before anybody else and before B bonuses. Overall for A's, I think we are more in the realm of 1m.
B bonuses are harder to get, but let's throw out a theoretical. They can be worth 2m for any thing being met. I'd expect Byram's to have that structure. The lowest tier for Byram to hit his B bonus is likely ranking amongst defensemen in goals. If he is top 10 amongst defensemen in goals, he likely gets the full 2m. Last year 13 goals would have been top 10. If Byram runs the 2nd PP or Makar gets hurt for say 20+ games, I don't think it is out of the question that Byram could be over 10 and approaching 13-15. It is high, but it isn't like he is winning the Norris either. He's just having an offensive output goals wise at a Toews/Ghost/Dobson level.
LTIR is different and more difficult, for bonus accruals. You don't get the same day to day accrual for it. There is a separate bonus accrual portion and if there is a bonus. It is applied retroactively to the whole season. As an example, if Byram maxes out instead of being treated like a 894k cap hit, it would go back and be 3.4m... but any overage caused by this would spill over to the next season.
All of this is manageable, it just all comes with pros and cons. If the ELCs perform, next year is likely to be even messier.