Welcome to the board.
1. Just... No. JPA cannot be allowed to try an rebuild value in a year that AA is trying to contend. It defies all logic. He should ether be traded for whatever they can get, or non-tendered. And to your thoughts about a defensive specialist being the solution, but then saying to bring up Jimenez after JPA is gone? Jimenez is exactly that. A light hitting defensive specialist, so you're somewhat contradicting yourself. Again, in a year that AA clearly means to contend, you need a proven catcher that the pitching staff can have confidence in, is a decent defender and at the very least can get on base at a respectable rate.
2. If the tumour thing is really the culprit of his poor play last year, then maybe he won't be a problem. But you'd only trade him if the jays are out of contention. If they're right in the middle of it and melky is hitting well, trading him probably wouldn't make sense.
3. See #2, minus the tumour angle. Rasmus could also very easily play LF with Gose playing CF if Melky is DHing more. This would assume that Lind would be traded at some point. And with a LHB heavy outfield, you would definitely want a RH hitting 4th OF that can handle CF every once in a while.
4. Contending years are no time for experiments to see if young players can handle a position. Even in limited sample we can see that Goins can handle 2b defensively pretty easily, but there's big time questions with the bat. Izturis is a good bet for a bounceback season and really, unless the Jays find a 2b via trade or free agency, the job should be his, with Goins either playing everyday at Buffalo, or as a bench guy.
5. Gose yes, Sierra... He's a meathead with no baseball IQ. Bench guy at best, and maybe he can be that RHB 4th of, but again, In a contending year, I'd rather see someone a bit more proven with a track record of hitting LHP very well. Losing Sierra to waivers would not be a a loss that matters.
6a. If the Jays are out of it and no chance of competing this year or next... Yeah time to think about it and kick start a full rebuild.
6b. Agree. AA paid too steep a price for a guy who could barely hold his own in the NL as a 5th starter, so he should be a mop up guy. Too bad he's making too much money to provide any value in that role. Good riddance. Let Jenkins provide mop up duty for league minimum.
7. No way the rotation, as it stands is enough to put this team in the playoffs unless everything goes 100% right. Dickey and Morrow would both need to perform like 1s or 2s and not get hurt, no erosion of skills from Buerhle, with 2 of Stroman/Hutchison/McGowan/Redmond(vomit)/Nolin throwing full time innings but again not getting hurt since the other guys would have to be in Buffalo waiting to jump into a spot if anyone got hurt. With MCGowan out of options, and big time questions if he can even handle a starters workload without his arm falling off mid-pitch, you'd have to plan on having someone taking his spot at some point. It's practically essential that AA lands another SP via trade or free agency to have any chance of competing, even if everything goes right, let alone when someone gets hurt. Chances are if he lands someone via trade, one of those other arms will be going the other way.