Hey Asser!
I am glad to see you in the forum!
1. No, the strategy will be the same; just the result will be accordingly.
2. Exactly!
3. I always suggest the students test the EAs on Demo, but if you change the lot, you do not need to test the EA again. It is the same strategy behind the EA.
4. Yes, if this is the same EA. But why would you trade ten times the same EA instead of 1 chart with 1 EA?
5. When you create EA for M15, you should be trading it on M15.
Let me know if I answered all.
Cheers,