Ok, I think I'm going to call this the end for now. I installed the new MAF sensor and took a test drive. Wow, what a difference, driving much better than without the MAF. I did not reset the codes (P0102 and P0112, both for MAF) as I was thinking they'll reset themselves after a couple of drive cycles like other codes. Is this true for the MAF codes or should I just reset them?
I took some data samples as well. Bank 1 RKAT is -0.17 & FRA is 1.00. Bank 2 RKAT is -0.20 and FRA is also 1.00. O2 sensors all looked like they were doing their thing! Very excited, but I only did roughly 20 mile test drive tonight because:
Out of the frying pan and into the fire HAHA It doesn't look like it's been leaking for long, and it is a very small leak. I got my borescope out and I think it's a crack in the tank at the usual spot underneath:
Sorry about the poor focus but it's essentially a point-and-shoot 1080p borescope. Tank, cap & sending unit are ordered and should be arriving mid-week, so I guess that's the next project for now. Once that's replaced, I'll put some miles on the car with the new MAF and verify I do not get the codes back. I'll post back after a few hundred miles. Thanks all for all of the help!