Would turning off the option in the Expert advisor, "Allow live trading" keep those charts from placing more trades?
Yes, but the EA will stop managing the open trades from stopped pairs.
Forum on trading, automated trading systems and testing trading strategies
Sergey Golubev, 2016.08.03 09:38
Where to check autotrading:
If you attached EA to the chart and you see "smiling face" so it is fine with autotading (in most of the cases):
If EA's face is not smiling and not happy so you can check everything once again:
It was for MT4 but MT5 is same with this case.
An EA trades either on the instruments that you attach it onto or on the instruments that you choose from its settings.
So in your case you either have to attach your EA on the right charts (of the pairs you want to trade) or you set it to trade the desired instuments only within its settings (if it had such option).
The already open trades only close if the levels (TP&SL) are set otherwise you will manually have to close them at some point , which should not form any problem.
Also you have to be specific upon designing a EA code it or tell the coder that it will only be allowed to trade instruments that are in market watch.
So you can add and remove instruments from and to market watch for the EA to trade.
The code should be written well in order to support this.