I recently did myoil pan on the 5VZ.
1. I didn't need an alignment after, I checked it with measurements and it was unchanged.
2. I would have gladly paid 1000 for this if I had that option. Took me 2 weekends and evenings after work getting this done.
3. Parts I'd recommend changing while in there: steering rack bushings if bad, cv boots if torn as your axles will be off, oil cooler o ring.
4. Change the differential seals if they are bad .. the diff will be out and easy to work on.
5. As you have oil leakage .. make sure to get the cover plate on the flywheel cleaned up.
6. Not a bad time to get your control arm bushings replaced depending on how bad the oil leak was.