@dmertzThank you so much for confirming all of these details.
Yes, to clarify, my HDHP coverage ended on Nov 30, so I was only eligible to contribute for 11 months' worth of the limit.
And indeed re choice of where to withdraw from. I found a post somewhere in which someone seemingly knowledgeable cited IRS anti-cherry-picking rules that apply to excess contributions when the person has multiple accounts (same thing for IRAs, too), which is how I arrived at withdrawing the appropriate excess contribution from each account, rather than all of the excess from one or the other. For example, it sounds like it would not be proper to over-contribute to one HSA and then withdraw an equal amount from a different HSA, since they would likely have different associated rates of return.
