350D/430EX Flash and Infant Birthday Party Questions

I'm trying to get my head around shooting with the 430EX. I have an infant's birthday party coming up and need some clarification.

I'm planning on shooting in P mode with a Stofen diffuser.

Is any angle other than straight on considerd bounce flash?

If the bounce wall / cieling is not white, should I shoot straight on?

Which ISO should I use on the 350D? The largest I would print is probably 8*10.

Any other suggestions appreciated!