833OD rebuild Qs

I'm going to be rebuilding my trans in the next couple of months and have some questions regarding what needs to be replaced and how to tell whats damaged.

Symptoms are:
1. Generally noisy (rattle, vibratons)
2. Crunching 1st and 2nd and really hard to downshift
3. Leaks around shift levers

I know that a bearing/seal kit will take care of symptom 1 and 3 and new synchros will fix the crunching.

I don't think I have the luxury of pulling the trans to do a complete tear down then order the parts.

Q1. Can I take the side cover off with the trans in the car and be able to tell what else needs to be replaced ( this is a daily driver )?

Q2. Is there anything that I should look for specifically that is a common issue that would cause a lot of noise other than bearings? ( like is it common for 2nd gear to be damaged or something like that? )

Q3. What are the "replace while it's apart" parts that I might as well do when I open it up?

It's a long tail, aluminum body truck OD.