Not snarky at all, and I appreciate the response. I am only considering BE because it is the incredibly penny pinching cheap passengers who will be flying with me. The difference in fare is $407 versus $362 per person. I offered the tickets to them to come along with me because they are literal (extended) family, and they would otherwise fly Spirit or the like and check bags and a) have an overall more miserable experience and b) potentially and perhaps end up paying as much as or more than BE (or potentially Main) on AA without all of the benefits that I can get to them for free. I only mentioned the scenario where I cancel and no one else does in case I get sick or something truly unexpected and emergent comes up; I have no reason to think I would not be able to take these flights. I mentioned the scenario where one of them cancels for the same reason - they would want to know how much it would cost them in the end if they dropped out. This situation is basically a one off, and I typically would never consider BE.

I've done something like this one, a while back due to a sched change and you may have to HUCA to get an agent that does this correclty, but I think the way to do that is they do the split first and then process the cancellation for the other passenger, somewhat similar to what happens sometimes when a pair opts for taking the last upgrade. So assuming four people I believe it will looke like the below ( the serious AA experts, feel free to correct me)

Original PNR Pax A,B,C,D on PNR 1
New PNRs Pax A,B,C on PNR 1
Pax D on New PNR 2

Pax D then can cancel PNR2 and will get whatever credit post-fees would be applicable on his ticket. Assuming you the status holder are Pax A, Pax B and C would still get your baggage allowance and such.
If you are the canceling passenger than they would lose all of your benefits, however if you have chosen MCE seats or the like, AA may not mess with the seat assignments that are already in place.

If I book this, domestic, I cannot change or cancel as an EXP without paying a $99 fee, correct? But would regain the SWU.

Am I correct in my understanding of the following?
I am AA Plat.
Booking a simple domestic ticket in Y.

Main Cabin (regular econ ticket): Earns at a higher rate, can be cancelled for a travel credit in most cases
Basic Econ: Earns at a lower rate, more limited cancellation/changes (but can still do same day standby if needed) - everything else is the same

All other benefits (seat selection/MCE, baggage, etc.) are the same

Is this correct?

Basic Economy fares no longer earn AAdvantage miles/Loyalty Points. From aa.com:

"Basic Economy fare tickets bought on or after 12:00 a.m. CT on December 17, 2025 will not earn AAdvantage� miles or Loyalty Points."

Everything else you wrote is correct.

Forgot about that change on earning.. thanks! Exactly why I asked.