DislikedBefore anything else, look into downloading historical tick data and importing it into MT4. You need to have a modeling quality (as reported by Metatrader) of at least 90%, if not greater, before you can have any trust in your EA.
Try to get this tick data from your desired broker.
Instead of just running backtests, spend time forward-testing the EA on multiple demo platforms. Find out which broker's price feed works best for your EA and use it.
Finally... if you must copy trades (and I don't suggest doing so from what you've described)...Ignored
I am concerned about how to run the expert(TP,SL,trailing stop buy, sell etc will be run on demo data) on most profitable demo account AND send only buy sell signals from demo to real account.So the expert will not be effected from brokers'(since the broker is market maker) manipulated data. Cheers .