The other day, in one of those TV specials made for Liella!'s debut, some images of the places that are going to appear in the anime, one of them being Kanon's house. The cafe where Kanon and her family lives is inspired in a real life cafe in japan (like Honoka's bakery and Chika's inn).

The place is called Cafe Casa, the outside of the place looks very pretty, and after find this place's official website I think I undertand why they chose this cafe in specific to be Kanon's house.

I decided to visit their instagram profile too and it really looks like a lovely place in the inside. Also, they explained on a post that the sign with "Cafe Casa" written on the outside of the cafe is from Lisbon (Portugal) and that the lanters next to the sign are from Granada (Spain), they really are true to this aesthetic.
There are other real places that will appear in the Superstar anime like Harajuku's Cat Street (I think the place where Chisato works is also based off of a place in real life Japan but I couldn't find a picture of it) but if there's a place that has already appeared in both the PV and magazine scans is the shrine where Sumire lives, based off of the Onden Shrine in Shibuya. This already in the wiki but after looking at the full picture of how is it going to look like in the anime...

I wonder in which house Sumire lives? The big one with galaxy green-painted walls? Hm... Nah, it has to be the red one.