Let's go back to your original list...
Apparently in a year I need new landing gear (from pitting), new exhaust, new starter, new engine gaskets, helicoils in the heads, new ailerons, new engine mounts and lots more. I bought it last year and used the annual as my pre-buy.
Unless you broke it this year, how can the new guy be at fault? He just found the problems.
Either last year's guy missed most of these items, or you damaged them all in a single year.
New guy just FOUND it, which is the whole point of an annual INSPECTION.
Or, they're working you.
Your comment about saying you think you made a mistake not specifying which mechanic did the annual is ridiculous. Are you really saying you wish you'd told them to use the guy who screwed up the pre-buy inspection so bad that he'd miss things again and put you and your passengers lives at risk?
The whole shop is HIGHLY questionable if they're trying to hang this on the new mechanic. Are you freaking kidding me?
Lets see...
Pitted landing gear - probably didn't happen in a single year.
New exhaust - maybe falls into "stuff happens". They do fail on old aircraft.
New starter - Why? Did the old one quit working or is there an AD or something?
New engine gaskets - Is the engine is leaking oil, or what? Was it leaking all year? Did you even notice?
Helicoils in the heads - WTF?
New ailerons - Even more WTF?! What's wrong with them?
New engine mounts - What was their condition at the pre-buy?
Lots more - Like what?
This list is so insane and your handling of it really makes me wonder if this story is even true. If it is, realize it's that crazy. Crazy enough I'm wondering what the hell these idiots are doing.
Let me guess. If it is a true story, the mechanic who "knows the airplane" was good buddies with the former owner and apparently found a sucker to buy this aircraft who wouldn't hire their own mechanic they trusted for the pre-buy???
What in the hell is really going on here? Are you pulling our legs?