I called the LATAM customer support, the person I talked to says I will need to retrieve bags from baggage claim of UA, then recheck in with AA since it is two alliances. It is during the busiest holiday hours. There are two UA flights to choose from to make the connection. One is 1h 45m, one is more than 3 hrs, to be safe, I picked the 3hrs one just in case I do need to get bags and recheck in. It is one ticket number as showing in the confirmation 045-xxx

One more question, I am earning AA miles on the AA-Operated LATAM flights, I provided the AAdvantage number. Should I see the reservation showing up in my AA account? I am not seeing it now. What can I use to look it up from UA and AA since they are the ones actually operate the flights?

And it seems like since it is a deeply discounted fare - Class Q, it is 25% of miles on AA. Would earning LATAM points makes more sense?