Do nothing. You have nearly reached the end of the exciting part, and are moving into the "watch grass growing" part.Should I add the oak cubes right after I rack it this weekend? What else could I add or modify over the next 48 hours?
Your wine will not taste like "wine" for months. At this point it's full of CO2 (which adds to the sharp taste), and checking pH is a waste of time.
The wine needs to complete fermentation, then drop gross lees, which is fruit particles. I'd rack into carboys, put it under airlock, and let it set a week. Fermentation should complete and a lot of sediment will drop.
I don't recommend adding oak until after this -- you'll have heavy sediment and if it's cubes or chips, they will be buried in muck. While it doesn't hurt anything, the wine is not as exposed to the wood.
Are you going to manually degas or add fining agents?