When I went to install the 7.6 firmware in ReplicatorG 0040, I accidentally installed Sailfish 7.6 (
So from what I can figure. you wanted to install 7.6. You did install 7.6. and then you tried to install just about every other firmware yoiu could get your hands on.
No wonder the machines confused, so am I :-)

I have tried pressing the reset button before, after, and at the same time I press the upload firmware button.
I can't tell if I just need to keep at trying to upload a specific firmware,
yes - BUT just the firmware you actually want. Don't go pissing about trying to install every other thing you can find on it.

It's the old adage: do one thing right. Not ten things badly.