I’m looking to make a bugbear rouge and would like to know if this would be reasonable with homebrew.

Anything is (theoretically) reasonable with Homebrew, but no.

• It’s a 2-handed weapon, so it requires 2 hands.
• Dual Wielding is only for melee weapons, not ranged weapons. So they could dual wield them as two clubs.
• The Ammunition property specifies that you need a free hand to load the weapon, so even with the crossbow expert feat you can’t reload while holding a second crossbow. (You technically can’t even use two hand crossbows at the same time and reload.