My tickets are as follows
GIG-MIA-JFK (AA 990, AA 490 arriving JFK 09:50)
JFK-BOS AA 1850 (leaving JFK 12:45)
BOS-JFK AA 1851 (getting back to JFK at 16:00)

I'll have one piece of checked luggage (large backpack...like 55 Liter). It is approximately 22" tall, if I don't overstuff it. I won't be able to pick up and recheck bags at BOS.

I thought about my options...
1) pick up my luggage at JFK; take airtrain to Term 1 and drop it off at the baggage storage; pay fee of 10-12$; take airtrain back to Term 8; and of course repeat the process 6 hours later.
2) Bring my luggage and Nicely ask the JFK AA baggage office people to hold it for me, since if I just didn't pick up my luggage, they would be holding it anyways.
3) Just don't pick up my luggage (nonvaluables/dirty clothes) and have it spin around the carousel and hope no one takes it. I'd Pick up from baggage claim office after the BOS-JFK flight.
4) Throw away all sizable liquids (sunscreen/bug repellent). Try get my 22" backpack through TSA security and leave in the AA Admiral's Club and hope no one takes my bag.
5) Go to the ticket counter in MIA and have the agent retag with MIA-JFK-BOS-JFK. But maybe that can't be done according to one of the responses.

Anyone have any other ideas?