I literally might be the only person who has personal experience with something like this. My situation was similar but not exact. Applied FM only.
I'm a DO student who took Usmle CS first, then two weeks later took the Comlex PE. Before anyone asks, I took the CS because there were some programs that required it from DO students. Yes I know, the correct answer is to not apply to those programs, but I wanted to be more easily compared to MD applicants since I was applying to ACGME only (and I had other issues). So far, during interviews, that comment "easier to compare" has gone over well with the individuals that have interviewed me. But no, no one has told me that I as a DO student who took CS - that it was good thing or bad thing for my application.
Anyway, I found out failed the PE and to this day, I still don't know what I did wrong. Then 2 months later (more actually) I found out that I passed the CS.
My PE score wasn't released until last week (passed) and I got a lot of interviews during that time frame (Sept 15 to last week). However, the day I released my new passing PE score I got an interview from a more competitive program than I had received previously. And no, I didn't send them an "update letter or letter of interest".
Before I can answer your questions. A quick point, I'm 95% sure that programs cannot rank you until you have passed all boards. I am aware that there could be conditional acceptance for residencies I just don't know how common those are, but I do know at the programs I've interviewed at - there have been several that explicitly stated that they could not rank an applicant until they had everything passed.
Now to answer your question, it's going to be a risk vs reward type situation.
How many interviews do you currently have and how many more do you feel comfortable in order to match?
Are you applying AOA or ACGME or Both?
How soon can you schedule a retake PE? What conditions has your school set in order for you to retake it?
Is there even an open CS date available, do you have the funds to travel to take it?
If you take it, will the score be available come rank time?