Hi,

You have a couple options with the flower stalk. Once it is done blooming, you can leave it on. You might get seeds in 9-12 months. You can even try to self pollinate it and see what happens. You can cut it off as well. Two theories on this issue. One says you keep it on until it dies, since it has chlorophyll and therefore supports the plant. The other one says it drains the plant of energy. No one really knows.
As for pot bound, it is hard to say if Clivias "like" being pot bound or just persist because that is all they get. I have a couple pictures showing some Clivias that were so pot bound they busted out of their pots years prior, had no dirt and still were in bloom. Once these plants were repotted, they recovered and look great. I'd say they like their legs to have room to run, but they will surivie for quite a while if cramped. In fact, one grower here in CA will get them to flower while still in a 2" wide band pot!

Hopefully this helps.

Enjoy your new plant.
Craig
Sacramento, CA