Hello Gowiso,
Glad to hear you in the forum. Bob gave you a great answer, cheers, Bob!
Yes, the different EAs you should trade with different Magic Numbers so you can follow their performance.
If you open different charts with one EA, when the entry conditions are there it will open trades on all charts. So if you selected to trade with 0.01, you will have 5 positions with 0.01. This would be useful if you take your profits on different levels, anyway it is useless.
Let me know if there is something else.
Cheers,