The Mistral is equipped, within it's blueprint, to handle the armament given to it:
Storage:
59 vehicles (including 13 AMX-56 Leclerc tanks) or a 40-strong Leclerc tank battalion
Troops:
900 (short duration)
450 (long durations)
150 (serving as operational headquarters)
20 officers, 80 petty officers, 60 quarter-masters
Weapons:
2 × Simbad systems
4 × 12.7 mm M2-HB Browning machine guns
16 heavy or 35 light helicopters
6 helicopter landing spots
Any change to add some other systems like the Mk41, CRMG, SAMs, Missile Cells, will require drastic blueprint modifications.
Changes to blueprints is pretty much making a different ship. The Mistral is priced at $600M because the French marketing team thinks it can produce enough ships to offset the R&D and also assembly line.
Much like the UAE's F-16 Block 60? Same design, but different layout. Lockheed charged for the modifications, but will repay UAE royalties if the jet sells.
This is a perfect platform for quick deployment of forces to war zones, what it lacks in armor , it gains in deployment speed and maintenance cost. The question is whether or not the Mistral will be capable of carrying and deploying the F-35Bs.