Yes, the MT4 plugin will handle requotes.

A broker server is normally not busy, unless the broker runs his business from home and uses his PC as a server. What you mean is that trades are rejected because no quotes are available. This happens frequently and with all brokers.

If a trade is entered and no quotes are available because it's weekend or for some other reason, Zorro just does not execute the trade.

If a trade is exited and no quotes are available, Zorro continues to close the trade until it is finally closed.

Your script can check with flags if any trade is currently pending, opened, rejected, etc.