Yes it is 2ft wide. It is a wonderful cage if you have the room for it. 

Ours never did

Chinchillas prefer more height than floor space They like to jump on multiple ledges and this cage just isn't set up for that kind of thing. Try the Midwest Critter Nation or Midwest Ferret Nation for chinchillas.

No, it does not have a lid or divider. Those only come with the Habitat Plus. Both are nice cages, easy to clean and easy access to the piggies.

only the plus comes with it

I don't think a totem lid would be big enough unless it's really large. We have 2 Guinea pigs in ours and never had a an issue with them getting out. G.P's don't climb and it's tall enough that jumping out is extremely hard. We have a plastic house with steps and even then they never try to escape, it's a great place to keep them. We have a standard cage for travel.

Yes you can just make sure you have a big enough table if off the ground

I would not put 3 guinea pigs in here. Just because they “fit” doesn’t mean it’s adequate. 2 females should be okay. For 2 males you made need more space as they can be somewhat territorial and low space can cause fighting.