If you have treated the tank with pancur many herbivourous snails will not survive for many years as the medication that is so good at killing hydroids is also good at killing other inverts.
If you have not treated the tank with panacur or similiar product a snail could be fine, make sure to QT it for 6 weeks, or at the very least give it's shell a very good scrubbing with a toothbrush. The hitchhikers snails can carry can be fatal to dwarfs, or many other fish for that matter. It seems extreme, but it is really good practice in the long run. Don't want your mom to know the present snail you got her killed all her fish.
Any hermit is a risk as they often tend to grow. I got the mini hermits as well some time ago, where supposed to stay about the size of a pea, ya not IME. Different species of hermits can be hard to ID especially when small but IMO no hermit in a dwarf tank is the way to go. Turkey basters and eyedroppers work good for detritus removal.
HTH
Fishyman, buddy ol pal. Posting links to other sites while seemingly common practice is actually considered very rude by many. It prohibits this forum from growing, makes the people here seem incompetent, makes the other site look rude, as well as brings up a slew of other potential problems. Best to keep links specific IMO. I ou want to link an article great, but just a random site is not good form.

Just saying. I know your fairly new to forums, and didn't think you were trying to be rude, but now you know, and knowing is half the battle.