Do EXP get upgrades on the domestic segments?

yes, as does a non-EXP companion (ie, sticker upgrades work like with regular awards, in my experience)

I redeemed and ticketed a BE award (Domestic RT Biz - BX1B) 10 months ago for flights last week, but needed to cancel the day before the flight - so now I have the value stored in my unused ticket number - and not business extraa points back in my account.

When rebooking, do I need to keep the same origin/destination, or may I book any domestic city pair - non transcon - where U space is available?

You should be able to rebook any itinerary within the zone covered by the original redemption. I've done this in the past, routing need not be the same. However, I would confirm the validity date on your "open" ticket. It may be a year from when you drew the original award/had the original booking made and ticket issued, and not a year from the date of your cancellation.

Anyone having trouble logging in to Business Extraa acount?

Ok, glad it isn't just me. Very weird the message I get though- 'We're having trouble logging you in. To resolve the issue, please contact American"

New to the program and attempting to use a BXP1. Holding a domestic reservation in L and flight shows J5, D5, I2. AAgent says no BXP1 space available.

Should I just run a search on EF looking for C as the wiki indicates and ignore all other booking codes?

I assume with no status, BXP1 is the lowest priority for clearing?

Yes, BE upgrades need C space, just like miles/copay and SWUs.

With no status, you're behind all other members with status who are trying to upgrade with miles/copay or SWUs (or BE certs). Depending on the route it could be very tough or no problem.

Thank you. But if C is available, I will be confirmed at the time the certificate is attached to the ticket and not wait listed. Correct?

Correct.

Looks like it's not so bleak; this was in today's newsletter thing:

"Quote:
If you've already completed the survey, we appreciate you taking the time to share your thoughts. Your feedback is incredibly valuable and will help guide us as we look for ways to improve our program. Your 500 bonus points will be posted by September 7, 2018."

Hey, that's today.. None yet.............

No 500 bonus points for me yet, either.

...and I am 300 away from a BXP3, which I could really use for a trip coming up in October. Gah.

Check your accounts. 500 points posted to my account sometime this afternoon.

Mine posted. This is consistent with my general hunch that a lot of Business Extra stuff has to be processed or entered or at least approved manually, and someone probably hit the button this afternoon.