1. Jewels gacha will and always be just using it during bonus rate up during the release of the unit you want. Aside from that it wil be nothing but RNG.

2. For your current team, your best bet is using Baphomet and Nergal with Morded with Sniper Shot. In the case you dont need Black Propaganda, Joan with Sniper Shot, in which you'd remove Baphomet for any other stronger fire kamihime you have. Brynhildr and Sol as your last two, Though you can replace Sol for another one of your SR fire kamihimes for better damage output since you have a 100% ediolon, but if the fight is too difficult, best to use Sol til you get better fire kamihimes.

From our current pool, you want either SSR Amaterasu or R Sakuya. SSR Enma would help too. The current SR roster of fire kamihimes is rather mediocre.