Hey man. Of course you can put multiple pedals in one enclosure, a bunch if us do it all the time. Typically there isn't an issue with interference between effects, but you can get some hum or ossilation due to the shared power. It's super easy to fix, just look up the humulator, I think that Neil posted a few different versons of it. It helps filter the power and removes the hum. Also, if you look on the main site at the offboard wiring section you can see how to wire 2 effects in one enclosure. This way you can control each effect individually. If you want three just add another switch and follow the pattern.
You won't need to worry about any sound degridation. In fact one dual effect that's been suggested a lot is the zen drive into a Timmy. It's a great stacking OD.