Glad to hear! 
Depends. In general it shouldn’t be a problem, it’s the same as if you’d run the tests on a brand new Mac, the very first time. The Simulator is in its default state, the one you get after you install Xcode, no previous version of the app is in there etc.
Performance: depends on what you compare it with, the standard machines are roughly the same as a Mac Mini / MacBook Air. A maxed out MacBook Pro might be significantly faster (depends on the project).
So in general it should definitely work, but in case your project requires more resources the Elite machines can be the better option as those have 2x the CPU and 2x the RAM of the Standard machines, which can be quite crucial for larger, more complex projects - see e.g. Compile time issue where due to the excessive usage of RAM the build took about 1/3rd of the time on Elite vs Standard (related comment: Compile time issue - #34 by vscafuto).