- Upload ArduinoISP sketch to UNO (what should the Programmer be set to at this point, because I already changed it and I dont remember
)
Doesn't matter, because you don't have a programmer yet. Upload it using the normal way, with the Board set to Uno. Then, after you've set things up for the ATtiny85, use the "Upload with Programmer" option.
Q2. Can I have the UNO connected to the attiny85 through the entire process or should I disconnect it when uploading the ArduinoISP sketch to the UNO?
You can leave it connected.
Your worries about messing up fuses are overblown. A chip cannot change its own fuse bits, so your Uno is completely safe. It's the chip you're trying to program with it (ATtiny85) that you have the potential of messing up, which is fortunately much cheaper.
It's possible to recover a chip no matter what configuration you set it to, but certain ones are much more difficult to recover from. If you accidentally program it to use an external oscillator, you just need to add a crystal to the board to be able to change the fuses. If you accidentally program the RSTDISB bit, you need to use high-voltage serial programming to be able to program the chip again. That requires constructing a charge pump (easier than it sounds) to apply the needed ~12V to the reset pin, a different sketch, and slightly different connections to the target. More of a pain in the ass, but not impossible.
If you accidentally use the regular Upload option instead of Upload with Programmer, it will try to upload the sketch to your Uno instead of the ATtiny85. And it will probably fail because the chip IDs are different. Just make sure to use the Upload with Programmer option every time.