The PROM can cause random fits like this, but nothing consistent that I have ever heard or experienced and I have run BPAC 95 suburban PROM code quite a bit although with modified pressure and shift parameters. And a key cycle should resolve the PROM error, even if codes were stored in history. I suspect this is not a PROM issue. It could be a wiring issue.
When the solenoids were changed out, did you do them all or just the shift solenoids? A bad Pressure Control Solenoid (force motor) may not code but cause a lot of other codes because there wouldnt be enough pressure to shift. When in there best to replace them all, since the PCS and TCC solenoid are most common 4L80E problems. All of the solenoids can be found for like $140.
Also if its possible that the wrong PCS solenoid is in there, like if a 92 or 93 4L80E was ever transplanted into it, or somone changed the PCS to the older version that works different than the 94+ years trannys. Need to check tranny pressure with a gauge into the test port of the tranny, compared to what scanner says PCM is commanding.
Your fuel lift pump is likely on a switch because the Oil Pressure Switch/Sender has failed, which is what sends it power when the engine is running. That is very common, unrelated to the fuse panel issue. And have you verified that half the fuse panel actually loses power, and is that the ignition power part compared to the battery power part? Bad ignition switch is common and sounds like maybe previous owner bypassed the ignition switch to give power to all the necessary stuff.
