I just switched to a new-to-me mechanic in town and I got a short list of things that need attending to in the relatively near future, and I'm looking for more experienced advice on which should be prioritized the highest.

First off, I switched shops because the last one apparently mixed green antifreeze with the existing Dexcool during a "courtesy check of fluids" when the car was in for unrelated service (tires). I found the sludge in the overflow and figured that shop just lost a customer, and now was as good a time as any to get a thorough chemical flush and switch to green. While the guy was in there here's the big stuff he found:

Leaking oil pan gasket (no surprise, but still not great)
Cracked serpentine belt (for the supercharger etc.; other belt is fine)
Seeping axles (not dripping, but wet)

Which of these would you place the highest priority on addressing?

Good news is no coolant in the oil or vice-versa, and the cooling system isn't damaged since I caught the snafu in time.