Just going off personal experience ( and this is not all hobs ) most need seperating when they come into season, they can and do fight ( i know people who have lost hobs ) especially if they smell your jills in season.
the jills should be fine together, so three cages needed.
Cheapest method if you are not wanting kits get one of your hob vasetomised, he will bring the girls out of season.
He will still have to be kept seperate through the breeding season though as even though he fires blanks he still has all his hormones.
Do you need two hobs ?