I have an upcoming trip in main cabin ORD-MCO on AA metal self connecting to a business class LATAM flight to Santiago, CL.

I recently learned about a free Explorist 90-day status challenge for corporate travelers (that I confirmed I qualify for). Here's the play I'm thinking:
- Register for status challenge
- Transfer miles from Chase to Hyatt
- Redeem for AA Status for a Day
- Use benefits on this upcoming trip

Here are my questions:
- Should I get Gold for 5k points or Platinum for 8k points?
- Can I use the MCE coupons on this existing booking? The person I'm traveling with booked separately. Is there any way he can get a MCE upgrade as well?

At the very least, I should be getting a checked bag and MCE seat (both of which I would have paid for anyway). Are there any other benefits I'm missing? TYIA