I used a 2 gallon glass container and I was only able to use 5 in there without crowding them. The other 3 are too large so I’ll plant those in their own pots. They can in excellent condition and assortment.
The better question would be are they grown without pesticide so they can be using a terrarium with live animals. I'm sure these are fine. I have use plants from Lowes and have had no issues.
I have come to find that the majority of these plants do not do well in full sun. If fairy garden is in well shaded area all day or on a roofed structure like porch or similar, they should do well.
No. The polka dot plants are more sensitive, they’ll “faint” on you if they are too cold or too dry. The goldfish plant needs water every day but the others don’t. The ivy needs even less water, and the Kalanchoe gets watered less than once a week. I use the Blossom app to track because I forget who needs what when.