Slow riding is not a factor, since most of them can't tell 5mph from 25 mph from inside their car. Spin the pedals fast in an easy gear and they'll think you're speedy, giving it all you've got.

I don't recommend riding on the sidewalk in most situations, rather stay on the street. Except when it feels too dangerous - it's up to your judgement on an exception basis.

Not in the middle of the lane, stay as far right as practical but far enough in (when the road is narrow) to discourage close passes. In other words, if cars squeeze by dangerously close without shifting lanes it's time to get further in the lane.

Yes, ignore the honks as much as you can. An odd thing about that is, as I got more skilled and confident the amount of honking decreased. I think I became more predictable and assured, and people react to that.