When people follow what?
You are probably asking about signal copying and the answer is no.
MQL5 signal copying system works quite differently, you select the part of your account that will participate in signal copying in signals
settings (0-95%) and the rest is calculated automatically by MQL5, based on signal provider's and subscriber's balances, currencies and
Here you can find the instructions about subscribing to a signal in MQL5.com:
Yes, about that, if you have the same leverage.
It gets simpler with larger follower's accounts.