My first folding bike was a Downtube FS with Velocity disc wheels. So they work with disc brakes for sure. However, you should be aware that:

1) You can't install a rear rack, as the rear section is on a suspended swing arm.
2) The frame is beefy to be sure, and the weight of the bike reflects that. It's probably close to 29lbs in real life.
3) The components are cheap. For the kind of riding you do, you're going to want to upgrade the drivetrain for sure.

So, while I am a DT fan in general, I would personally not choose it for the kind of commuting you're doing.

I have owned both Brompton and Bike Fridays. For your purposes, I would choose the BF for customize-abilty and maintainability. The Brompton has a lot of proprietary parts. And it looks like you will be putting wear and tear on your bike.