If I have 2 separate accounts with different trades and open up the 'Currently Open Trades' view under 'All Trades', does it show me all the combined open trades in both accounts, or just the trades from the one account.

It will show the combined open trades for both accounts. If you wish to view the trades for each account separately, you can put the trades into two different 'Trade Groups'. You could then open 'Currently Open Trades' for a desired trade group.