u/Fabulous-Ideal-6528

Noticed a small wet spot on the first floor ceiling this morning, corresponds exactly with where our bathroom shower drain is on the floor above. The shower is probably 10-15 years old (don’t know exactly as we bought the house two years ago - judging from the rest of the bathroom fixtures). I took part of the drain apart and a lot of the caulk (I don’t think they used silicon) was dried out, and the plumbers putty was old and cracked. The rubber gasket was wet which further makes me think this was the source of the leak. So my questions are:

1. Do I need a new drain, or is it enough to reapply new silicon/putty and reinstall the existing?
2. One side of the drain is more vertically offset from the shower pan than the other (see pictures). We’re talking 1/4” on one side vs 1/16” on the other. Is this a problem, and how do I mitigate it?
3. It seems like most recommendations I read online only talk about silicon and don’t mention putty. Is this a new thing? The putty seems to have held for a long time from whoever installed it before, why wouldn’t I just do the same thing and hope it holds for another 10 years?

Thanks in advance for the help. I love DIY projects but haven’t dabbled much in plumbing before!