I started mine around the first of the month (in vermiculite, too) and have a bunch of little seedlings, certainly more plants than I need!
Sweetie cherry tomatoes
Better Boy
Beefsteak
Cherokee Purple
Early Girl
And a few basil plants, Genovese and Red Freddy
And some peppers for a friend, Ancho and Banana
Plus some spinach and lettuce. Had some trouble finding lettuce seeds this year for some reason, but I found what looks like a nice mix at the hardware store the other day--5 different varieties in a pack.
And I have baby onions up, too.
If that little greenhouse is like the one I have, they're great! I take mine apart and use the pieces to make an extra level of shelves in my greenhouse.
And they would just as soon as blow away outdoors as look at you, so yes, by all means anchor that thing! I ordered a somewhat larger version of that same thing to use for the tomato plants when they start to drive me out of the greenhouse! Which always happens. Sigh. Do I really need 30 tomato plants?