Here's my 5 cents.
First, such a low distance from the sun deep-fries planets down to the heaviest, most refractory volatiles. You should consider making one of your moons an extra-dense iron planetoid. Mevron, for example, could be made of iron meteorite debris and have an uncharacteristically high gravity for a body of its size. Tiny tot of a moon.... surprise, motherlover, 0.7 g!
Second, high heat + tidal heating from a gas giant = LOTSA LAVA. You should consider making a lava world similar to the moon Infernas from the Planet Cyran pack. Perhaps adding lava seas to Jakis (in addition to Old!Moho hot atmosphere) will add some extra flavor to it.
Adding other moons, that I do not recommend. An epistellar gas giant with three moons is already stretching belief. Tiny Bulldur, surprising iron Mevron and Mustafar-like Jakis are enough (and unique, the rest of the Kerbol system does not have that).
And BTW, I'd make the rings near-black and wispier, not light gray.