Start with the AC10, and move up in a couple years if you outgrow it. I have a stock AC10, Ric 330/12, Ric 620/12 and a jangle box, and I'm happy with it. I do sometimes use a 12 inch extension speaker (cuts out the internal) or a 2x10 cabinet. I like the internal 10 better than the 12 I have.
I use a splitter when not using a stereo pedal/effects unit. I think when using a stereo pedal/effects unit to two amps (or to any two destinations) you won't be in danger of shock or ground loop (probably). Have you tried it yet?