Lots of questions here... man I should not sleep at night
OK what you get a 7th level 100% depends on what class you are taking. If this Gand is taking level one in Jedi s/he gets +6 (+Con modifier) in HP, +1 to Second Wind, +1 to all Defense bases (take the best of your other classes though so I think for this Gand it would be +1 Will Defense), gains the feat either Force Sensitive or Weapon Proficiency (lightsaber). You have to have Force Sensitive to take the class so you have to take that one. And you gain one Talent, either from the Jedi class or any of the Force Talents found in the Force section.
I would think that the quick-deploy folding stock counts as a minor upgrade.
As for additional gear remember this is a pretty small out of the way mining colony world. They don't have lots of extra stuff that you would not get from miners. You could get decoration caps (remote controlled, etc) and even some explosives here. But I doubt that any miner has much use for smoke grenades (or grenades at all), jet packs or sensor packs. You will have to go off world for that or you could order it special (use the Holovid to call in an order and have it delivered on the next transport, but it might cost extra).
You guys have some cash already (its still listed in the Rogue's Gallery I believe). The prices for most of the items you might want are on the first page. You will also get some additional credits here before we move to the next adventure, which will be partially on a more civilized world where you can also do more shopping.
For Jihahna…
Sure you can modify the helmet that way (strip out the visor and filter) and discharge the helm BUT I might think you would lose 1 point from the Fortitude bonus (I almost want to say from the Reflex also but not 100% sure). You have less armor and in D20 armor is sort of a full body thing and when you have less of it you don’t have as much protection. BUT at the same time is kind of just flavor etc.
Think of the Scout armor as “similar” but of a different type than the Scout armor seen worn by the Stroomtrooper speeder bike pilots in Return of the Jedi. That is sort of what it is based on as the Sith Empire is very similar (But totally different!!!) then the Galactic Empire that we see in the movies.
I am fine with your lightsaber acting like a vibro-bayonet, when used two-handed and mounted on your blaster it does the base damage and when used one handed like a blade it does the same lightsaber damage.
Hmm the vibro-bayonet in her cyber-knee is interesting but the blade is going to be sticking out of her leg when she walks around. It’s not a switchblade

although I can see you trying to modify it so that it could be… I am fine with you mounting there per-say BUT when and if you fall prone it might mess it or you up…
For tgalssy, normally lightsaber colors are indistinguishable from each other. They provide you nothing cool other than style

hehe. Now the heroes found some special crystals when they were leaving the Infinity Gate and these will grant those who craft their own lightsaber with them a minor bonus. It does not matter what color you use, you decide what you want and what color you want.
This is mostly for Kacela and Jihahna (and Reks who left with a couple) but if after you adventure with them I might rule they had some extras that they can share with you so that you can incorporate one of these minor boons into your own. We can already assume that you have crafted your own lightsaber (it is part of being a Jedi) and that you already gain the base bonus of +1 to your attack rolls with it. This applies only to a lightsaber that you, yourself have crafted.