Ok, so technically removing the stem between hits works. But it's still draining your battery sitting there not heating anything, and if you get into the habit of heating it up and taking a hit and turning it off, and repeating, you will run the battery out sooner than normal.
But more importantly, if she doesn't want to fiddle with a lighter I'm not so sure she is going to want to fiddle with a very hot piece of glass between hits. You have to place it somewhere while it is hot in an upside down-ish position to keep the herb from falling out. I think she will hate that and think the vape is a pain in the ass.
Desktop performance in a portable is hard to achieve. The Crafty and Plenty come to mind, but they are in the $370 to $500 range. The MiniVap would be perfect, but it is in the $500 range. The Solo is a great vape, but not if you are into one hitters. I wish you hadn't said a lighter is out of the question, as there are several very good, cheap portables that can knock some desktop units out! The Lotus, Daisy and Lily come to mind first.
In the end, I think the Solo is the one to get if you are dedicated to having an electric unit. She will enjoy the sessions and will be in the right place when it is over. But if she can get past the lighter issue I think she will really like some of the ones I mentioned more.