So, does Force Friday take place tonight at midnight (like last year) or is it actually tomorrow?

Midnight is tomorrow.

We already know that the Partisans were a Rebel group.

...or a Scum group that sometimes works with the Rebels...like Dengar, Bossk, IG-88, Concorde Dawn, or Black Sun sometimes work with the Empire.

Nope. Saw Gerrera's Partisans are directly mentioned in Aftermath as a Rebel-affiliated group that fought the Empire in exceedingly brutal ways, that often maximized collateral damage, but they were effective so the Rebels provided them supplies and equipment, whom are later criticized by New Republic representatives as too extreme, even for the Rebel Alliance.

The Partisans may hire or work with criminal organizations, but their cause is 100% rebel, and we've known this since the faction was revealed.

I guess we'll see soon enough! ;-)

So, does Force Friday take place tonight at midnight (like last year) or is it actually tomorrow?

Midnight is tomorrow.

Realistically if there was anything my money is on scum epic or maybe a xwing campaign.

Though I have to say it's probably going to be an announcement. Id be very surprised nothing was leaked if stores had some items now that are suppose to be on sale.

Plus they are already showing what's going to be available, so there's no reason why ffg would still be withholding items until tomorrow. You can go to websites now and see whats going to be released