the lengthier the wheelbase, the more comfort a car is as it doesn't bounce as much as any variance on road surface can be distributed over a larger area.
Many vehicles use torsion beam, including city, khyber and few others which are known for stiff ride. I'm expecting a ciaz / vitz like suspension, not as soft as corolla but still adequate comfort and not a harsh ride like you know which outdated design 1.3 and 1.5 car 
Grande has this acoustic glass windshield, noise isolation isn't much different from other versions of corolla.
There are other things to consider as well, smaller cars have more tyre noise, there might be difference in thickness and quantity of soundproofing sheets beneath mats, dashboard and firewall etc. but i'm sure like all toyota's Yaris will fare well in all variants.
I'd recommend to go for Yaris as corolla will be replaced with a newer gen.