To further add to what Nikos said, the major thing you need to keep in mind is that the settings you can configure apply for every single EA. That being said, if you set the risk settings to high (2% per trade) and trade with 3 EAs at the same time, and they go on a loss, this would lead to 3*2%=6% loss of your account balance which eventually will lead to the challenge being lost due to drawdown. So keep in mind this when trading with multiple EAs.
For the second question, over the weekend the app uploads new strategies if if finds more profitable EAs than the current. So you might expect to see new EAs after the weekend. The stats in the app are auto updated every 30 minutes and at any time you can see which are the top performing EAs with the current market conditions.