Also “in real life”, or “in the flesh”
Yes, this. Using the old city of Venice as a base, or model.
This is a context sentence from Jisho for ベース
キューバリブレはラム酒をベースにしたカクテルです。A Cuba Libre is a cocktail with a rum base.
It’s a slightly different meaning of base, but isn’t that a similar format, using に?