Are you sure it's not a squeeze clamp? Most likely it is not leaking from the clamp. Either the hose has a whole right next to the clamped area or the heater core is leaking. I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa
Your transmission is probably not even worth rebuilding and before you sink a bunch of money into it you should evaluate the repair costs v.s. what the car is worth overall.
If you can do it yourself and get another transmission from a [pull it yourself] junkyard; you might consider that route. Otherwise, consider what you could sell it for "as is" to some somebody that can do it themselves when evaluating the situation.
In other words, leave your emotional attachments to the car aside and don't get into a money pit. Take into consideration that it also may need a bunch of other parts like replacement drive axles.
The O2 are not ready because it takes some time for them to complete there self check after clearing trouble codes. This will involve a few drive cycles. Once the evap problem has been resoled, the check engine light cleared, you'll have to drive it for a couple of days to get everything in the "ready" status. I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa
When they adjusted the brakes ,its possible they made it so you can now hear an existing issue. What's most likely happening is that your slave cylinder has frozen in one position. What this causes is for only one brake shoe to expand, not both. I'm assuming that they are drums in the rear. Replace and bleed both slave cylinders, problem solved. This exact problem happened to me about 6 months ago.
I'm guessing the antitheft worked then? Getting the codes and reprogramming a new switch, because it sounds like your switch is damaged probably beyond repair, is most likely a dealer only job. Be sitting down when they tell you how much!!