So I have 4 different strategy running on a 2 different sim account trading on live data (1 each for managing equity and 1 custom strategy with minor differences).

I notice that only one of the strategy gets fill and the other dont, even though the only difference is additional code on additional entry with different parameters. I was expecting both strategy will enter at the same time since the base code that met that condition is the same.

My question is, do the # of strategy we run affect the efficiency on which strategy get executed first?

Is the custom strategy with minor differences acting against the same instrument?

Quoting 

If you want to trade against the same instrument with separate strategies, separate accounts will be needed

Reference:
https://forum.ninjatrader.com/forum/ninjatrader-8/platform-technical-support-aa/1130152-multiple-strategies-in-one-account