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.