Castellania:
No surprise that there is a castle on a hill (there are literally dozens of towns in Italy whose names start with "Castel..."). But what about the spread eagle and fleur de lis? Both Guelph and Ghibelline sympathies?
The Giro passes through Vercelli, which seems at first sight to have a close affinity with St George, though the cathedral favours the local St Eusebius and the basilica St Andrew.
The motto is actually "Potius Mori quam Foedari" (Death before Dishonour), not "... Poedari" as shown. It probably refers to the many sieges that Vercelli has endured.
Biella:
Blazon: D'oro, all'olmo al naturale nodrito sul terrazzo erboso di verde, all'orso al naturale passante ai piedi dell'olmo.
"Olmo" is, as I guessed, an elm tree, and not as is suggested elsewhere a beech. Sadly there seem to be no bears left in the vicinity of Biella.