Anh map

As sjr09 stated earlier,if a person shows exposure to TB then the chest xray will likely be done.
For TheBears, be sure that your spouse brings any vaccination records to their medical appointment for the doctor to evaluate.
OP, if your medical was within the last 12 months you have been screened for TB. If you have your records it is unlikely that you will need anything further.
The K1 visa holders will go through this TB screening prior to AOS (typically when their medical is done as part of the visa petition/application process). If you're medical expires and/or you do not have the vaccination record you may have to undergo a new medical exam and immunizations even if you are adjusting status from K1.

I suggest that you go and speak with a qualified immigration atorney to discuss the specifics of your situation.

Actually the K1 expired upon use. Her I-94 expires on April 17. This time "out of status" is normal for those who enter on a K1. The AOS application process will take some time. You've got the NOA1 to show that the I-485 has been filed. Her status is "protected" during this time. If she needs to travel outside the US then be sure to get the Advance Parole document (ideally before leaving the US).
You should not have anything to worry about.

The I-864 obligation does not end if your income drops below the minimum needed for initial approval. Once accepted you are the primary sponsor.
If your spouse has not yet received the green card approval you can pull your affidavit of support and then he could not adjust status and obtain the green card.

What the alien fiancee needs is a method to secure LPR status, not simply a work visa as the current federal law would not allow for adjusting status through a same sex marriage. When that law might change is anyone's guess.
It may be well worth the time and expense to consult a qualified immigration attorney. And probably one in the Gay and Lesbian community to get a good sense of what lies ahead. The alien fiancee doesn't want to run afoul of the law and wind up facing some of the harsher consequences such as a ban on adjusting status or worse, deportation.
Regarding stand up, good luck to her on that. I lived with a marginally well known stand up for a few years and it was a tough industry.

It's telling you to sign the form. Nothing about previous spouses.

Including the joint bank account cannot hurt. The foreign funds won't matter as they can't be easily gotten at in the event that they were needed to satisfy a claim. They tend to want to see US based assets.
Based on what you've said about being above the required income you should be ok.