a1) Lei, vorrebbe mangiare qualcosa ? a2) Vorrebbe mangiare qualcosa, lei ? are both correct; I would prefer a1. If somebody is in my home, I would ask: -- Vi andrebbe un the' o un caffe' ? (I assume more than a person) -- Che ne direste di prendere un ... -- Volete qualcosa da mangiare ? b) We have many many terms for 'Via' Viale is usually wider, and might have two parallel roads, one for each direction, eventually with a narrow strip in the middle with trees. Another one is "Circonvallazione", it is like "Viale" but connects far away points in the city, eventually making an arc of a circle. There is a town (Forano) in a beautiful area North of Rome (Sabina) were the term for 'Via' is actually written 'Vocabolo', this on the streets' notice; go figure! c) 'Il fiore', 'i fiori', masculine noun; don't be mislead by proper names, as the gender sometimes don't match with the similar sounding common noun; actually Dellafiore, or Deliafiore is unheard of; Dalia is a flower, anyway.

a) Quel "Lei" is not really necessary, in normal circumstances. It could go if, for example, if there are more people to talk to, and after speaking to someone, maybe talking about eating something, you turn to this person and say "E lei, vorrebbe mangiare qualcosa?" b) "Via" is usually translated as "street", "Viale" and "Corso" are usually translates as "avenue" and "boulevard"; usually, a via is a normal city street, a corso should be broader, with both ways and a couple lanes, viale has or should have plenty of trees and should be an elegant road in an elegant district.