You don't talk about budget or where they will be riding.

If money is of little consequence, I'd have them riding Surly Long Haul Truckers.
It can be ordered with 26" or 700c wheels, and cantilever or disc brakes.

If the guys are short, I'd go for the 26" wheels. The brakes can be their choice.

These bikes are built to carry weight and do well with a granny gear for out of shape cyclists. LHT's come with 36 spoke wheels. The modern hybrid is a little too sweet for my taste. With compact cranks and carbon fibre forks, these bikes are not geared low enough. If a carbon fibre fork folded under stress the rider would face plant pretty severely. Spoke counts are down around 28. Not nearly enough for your big buddies.

If you are on a budget, I'd shop for 5 to 10 year old hybrids with steel forks and triple cranks.
I'd have the wheels tuned then ride them until they break. If the guys are still interested in cycling then they can purchase new 36 spoke wheels.

Good luck, and report back when the 3 of you do your first century.