3. Not positive you can put an IRA into a 401k (you can do the opposite for sure)
You can if the employer's plan allows incoming rollovers. Mine did; not all do.
Does anyone have any other cons to consider? Do I have to do anything special for federal tax purposes (I assume this is not a taxable event) or does timing on when I do this matter at all? I'd love any more insight into this if anyone else here has researched this.
Thanks!
You don't need to do anything, and you're correct that it is not a taxable event.
Timing-wise, there is something about your account balances at the end of the calendar year on Form 8606, so if you can get the rollover done before the end of the calendar year that's probably a good thing. Difficult to do given what day it is, of course.
The only other thing I know of to consider is if you have a basis in your traditional IRA, which is usually from making non-deductible contributions. If that is the case, then things get more complicated. I haven't dealt with that situation personally so I don't know what the options are exactly, but it might be possible, for example, to rollover the non-deductible portion into a Roth 401(k) at work.