As we know Steven and the gems have added Peridot to the Crystal Gems and have given her immense support in her endeavors. However, Lapis, who had taken a liking to Steven and only Steven (reminds me of a certain green gem) may be a bit more hesitant to join.

She most likely will join, but after much development in getting to know more of the members. I see her as still connected to home world in a "it was my home",rather than "my home" and probably doesn't have negative feelings towards it...yet.

She, like Peridot, will probably grow attached to Earth in a way where she doesn't want it to be destroyed and possibly to were she will fight for it. If so then the Crystal Gems will have Lapis, a strong water type gem, capable of a lot as we have seen, and with the help of The Crystal Gems they might even win the war!!!

This has been Cuco,
Stay fresh.