Hey Simon,
Very smart questions here and points. These are things I have been stragleing with as well.
What I know for sure is that the Portfolios are for MT4 exclusively. This is because MT5 with most of the brokers do not support hedging, and trading with the portfolio EAs is hedging indeed.
Personally I am trading the EAs from the walk forward optimization course on my broker (different from what Petko uses) and I do well the last 3 months.
The idea is that we remove the strategies that do not perform well, right? So even those are different strategies from what Petko would be removing, still I will remain with the proftaible strategies from my broker.
Petkos courses are really amazing and I always ask him after I complete the course :)
Kind regards,
James