20 Starcrystals. 100 EP. 200 EP is nearly half the cost of the fighter.
My bad, but yeah, ditching the Starlances for say Suncannons (30EP) would drop the total cost down by 140EP although having a Fatesever (60EP) replace a Suncannon would make it very deadly against other strikecraft and still drop the total cost by 110EP.
Regarding turning the Caravel into a light carrier, here was a design I cooked up a while back:
[] Light Carrier Caravel Example
-[] Trade in 2 Weapon Slots for 2 System Slot
-[] 1x Heavy Las-Lance -1 Heavy Weapon Slot
-[] 2x Las-Lance Weapon Batteries - 2 Weapon Slots
-[] 2x Æthersail - 2 System slot
-[] 1x Plasma Thrusters - 2 System slots
-[] 2x Las-Lance Point Defense Battery - 2 System slots
-[] Holo-Field -1 System Slot
-[] Grav-Shield - 2 system Slots
-[] 1x Hanger - 1 System Slot
Keeping the Las-Lances because these things should be staying far away from any enemies and Las-Lances should be our longest range non-exotic unless the the Suncannon's range advantage over regular plasma weapons lets it match them.
This is way worse than a Dhow in the carrier role as the Dhow has 10 System Slots at base, and only 1 fewer Weapon Slot so we could take above design but either add an additional Weapon Battery or turn that into an extra System Slot for more hangars or some other piece of 1 System Slot cost equipment.
Edit:
Of course if we made a Dhow we would need to build a bunch of fresh hulls rather than just refitting one of our existing 52 damaged Battle Caravel hulls