I couldn't log in for a while but I'm back on now.

I was able to place multiple orders without closing previous trades with the 0.1 tmbtc test provided.

And so I’m guessing it's safe to assume that the extra funds are provided as margin? If that's the case, shouldn’t there be some kind of warning for users that, they are trading assets with borrowed funds? This could lead to serious problems and debt if not checked.

I can’t find any data in my open orders tray.

The P&L never updates

I still don’t understand the concept behind frozen funds and how it would benefit users.
You’ve done a good job explaining it here, but not many users will check on here. You should have a tutorial made, and even at that expect to be bombarded with many questions.

My account logs out automatically, even when I’m still active.

My general feeling is confusion, but then I am not a pro trader. I have only dabbled in it a few times, but someone well versed  in trading may feel otherwise.