Yes.
Irrelevant / pointless. If you walk through the calculations in Form 8962, you'll see that it starts with your AGI for the whole year, then calculates your portion of your health insurance premium Congress has decided you contribute on line 8a. If you end up having month to month variations, that 8a amount is divided by 12 on line 8b and then used to fill in lines 12c through 23c.
So it won't matter when you take the lump sum because it will be included in AGI (on line 2a) regardless of which month in 2025 you take it.
I guess the only thing that comes to mind is that it might make sense, if you have the option and it works with the rest of your tax picture, to take the pension lump sum this December so it shows up on your 2024 taxes. Obviously a tradeoff between your 2024 and 2025 taxes, so you'd have to figure both years both ways. Figuring 2025 taxes will be tricky since you're new to the tax implications of ACA and it's a moderately complicated calculation to do in terms of how it interacts with the rest of the tax return.