Hell.
I didn't know the skells can be broken. Anyway, do I have to buy skells for my crew? Because my main ones is my avatar, Elma, Lin and Lao and I bough 4 skells.

1 Inferno for me and 3 Lailahs for them. I'm not interested in the other weaklings like Doug and Gwin, although Irina is cool but considering that I can't have more than 3 party members, I'm going to alternate 1 lailah between Lao and Irina.

Currently going to chapter 8.

Each team member must be assigned their own skell. However, you can freely reassign skells to anyone who has a sufficient level to pilot it. Each skell is insured three times, but when it is destroyed the "B Circle" event pops up; if you get a perfect on that you won't use up an insurance to replace it. The AI automatically succeeds at this event, so your teammates will never use up the insurance.

Thanks! Then it means I did not wrong buying their own skells. Chapter 7 was a piece of cake.

At what level can you start registering other skells? I bought a second one when I got my free one since I really wanted a Wels, what it said I wasn't at a high enough level to register it yet. I want to start giving skells to my other party members since I found out here that they won't use up insurance when they break.

Each Skell has a Frame Level. The character you wish to assign it to must be at least at that level before you can register it to him/her. The free skell is at level 20, all others are at least at 30.

Ah okay. Damn, that's gonna be expensive. Any tips for fast money?

Setting as many probes as you can, finding the scenic spots, and then setting up chains with Research Probes. In general you want to keep an eye open for hexes with sightseeing spots, as each is worth several thousand when connected to a research probe. Northern Cauldros in particular is a great place to set up Research probes. If that proves difficult (especially without flight), eastern Oblivia is a great alternative. Doing this is not only helpful for racking up cash, it's essential to beating a pair of quests down the road, where you'll have to earn $70k and $130k respectively in a single return.

How do you get more research probes? All I get are mining probes.

They're unfortunately very rare. A handful are handed out as quest rewards, but the majority come from salvaging Mechanical debris. I'd focus my energies there: it shouldn't take long to get at least two or three, which when paired should be enough to get you going. Also, Duplicator Probes can be used as ersatz research probes if you put one next to a research probe, and Booster probes can amplify your research probes in the same manner.

Of course, those two are even more rare, but maybe you already have one? I think Kristy hands out one of each as a quest reward.

I just finished chapter 8 and it was a great one, the story was moving pretty slow but I´m guessing things get more hectic after the events of this chapter.