Yeah, I was using this as the reference, it only listed an Analog 1, 2, and 3, no 0, and that first ATTiny core I tried wouldn't accept A1 as a port (pinMode(A1, INPUT)), so I had to use the digital port number, which was 3 and 4 (physically 2 and 3).
I haven't ever tried using the RESET pin for I/O. Will the ICSP programming still work with reset disabled? Very odd that that one ADC won't work for me with two different cores. I haven't found anyone else mentioning it, yet I've run into it in two very different projects now. I even use a "real" ISP programmer now. (USBTinyISP)