I personally don't believe in keeping them inside. Despite the fact that they are so tiny, they are in fact chickens and chickens do best in a flock.
How many eggs you get would really depend on the bloodline. My eldest serama Widget is now somewhere between 5 and 6 years old, still laying eggs although most of hers are now infertile. Widget has what has become an annoying habit for me. She lays just enough eggs - between 3 and 6 - to go broody on them. Widget raises her chicks for 6 weeks, kicks them to the curb, lays another 3 to 6 eggs, goes broody again....all year round! Since her eggs are now mostly infertile, I usually get tired of fighting her broodiness long before she gives up, so I end up buying her chicks and she does the rest.
I purchased Widget from a serama breeder that was getting out of the breed.
Not necessarily, as I've heard from other serama owners. Widget may be the exception to the rule. I've told my husband more than once that I think the real reason the breeder wanted rid of Widget is because the bird is rarely ever not broody. She drives me nuts with it, but I love her.