This is our 6th child, 5th girl.
Pretty name and meaning, but the lack of history would probably be a turnoff for me as well.
If you're looking for an out, it's also rather close to Sarina. Right now all of your kids have very distinctive names.
I'm not a big fan of Solara for the reasons you and the previous poster listed.
I would steer clear of it for the Toyota factor. It instantly came to mind as a model of car.
Other similar names that you may want to consider:
Solene (pronounced SO-len) Soleil (SO-lay)Sierra