Fyi, I ended up replacing the Qest T-fitting with a SharkBite push on T-fitting. Doesn't leak a drop. I now have hot and cold running water.
Thanks for everyone's help, especially Dave G and Driftless!
There's, hopefully, just one last repair. The telescoping faucet in the galley is leaking again. The foot pump and connections are fine, its leaking from inside the telescoping part of the faucet itself. There's an o-ring at the base where the telescoping metal nozzle comes out of the plastic part. Probably due to wear, there's a small gap between the o-ring and the metal telescoping part, as you can see in the first pic below.
I doubt they sell replacement o-rings. From what I've seen, its probably a Whale Pumps brand telescoping faucet but can't say for sure. I was thinking before buying a new faucet I'd try wrapping the metal telescoping part with just a couple wraps of teflon tape and see if it stops the leak. Or put a small washer below the o-ring. But I can't get the o-ring out. Its been out before when the whole faucet came apart.
If anyone has experience repairing these telescoping faucets, please let me know.
Thanks!
Greg