Are these bike trails doable in a hybrid bike? And are you allowed to walk these mtb bike trails?

I would go to Laurel Hills with a hybrid. Meadowood will jar your teeth!

Certainly doable, but be really careful when going over rocks and roots to not get flat tires! Laurel Hills MTB trails is a good place to go if you want a pretty smooth MTB experience. It's just pretty much entirely gravel and easy climbs and descents.

Yes you can walk on them and I would say they are doable on a hybrid just take it easy on the designated mtb trails like "Yard Sale" and "The Boss"