I think I wasn't clear - access to the MT4 account is not given only with the demo. With a live account you will have normal access through MT4 and also through Myfxbook. Only with a demo it is limited as the demo has no expiration date so access to the MT4 will allow to copy the trades with no permission from the provider.
Creating a live account would be a regular process after which you'll have to provide the master password so AutoTrade can mirror the trades in your account - important to note the password is saved in an encrypted format on our servers, so no one can see it, not even us, which ensures the complete safety of your password. Everything is automated so no one ever sees your password.
We haven't measured execution times, however they occur in less than a second in normal conditions. In special conditions such as high volatility after a news event when a broker denies orders, AutoTrade will keep trying to mirror the trades in your account at an equal or a better price until succeeded. In any case we don't allow scalping systems, so execution times would hardly have an effect on performance (statistically speaking, your trades will get the same price on average as the provider as some will have positive slippage and some negative).
In theory, anyone can own a MT4 server and manipulate data, for that reason we do not allow shady/unknown brokers.
I will forward the the suggestion regarding manually closed trades to the dev team - that is a bit complicated feature but will be definitely added.
As to how exactly AutoTrade works - that is not a secret. Most traders/users don't understand or don't care about it, which is why we didn't over complicate things with elaborate explanations. We basically run MT4 terminals which interact with each other as Master>Slave relationships. If you have anymore questions, do ask and I'll be happy to answer 😄