As far as what animals to carry, if you look at the # of threads in each forum, you'll see which are the most popular... it's pretty clear.
I would tend to go with a variety myself.
Which bedding to use for a shop? Here you have to go with looks. Aspen shavings or bark mulch look nice and won't have any ill effects on the animals. Then you throw in a couple of the fancy hides, fake plants and water dishes and you're set. I'm sure the shop will LOVE it if you sell a reptile and all the "useless junk" that they carry too.... Useless in that it is nice to look at but not necessary
I'm not too sure how successful you would be if everything was on newspaper but you never know. lol