Your setup should work for what you want to do. The idea of Qubes is to separate your computer into compartments, so one Qube for each type of connection is part of that idea.
That sounds worse than Tor. Tor will build a different circuit for each website you access, whereas a VPN cascade will leave you with a fixed IP.
Lots of people have been working on traffic analysis of Tor, but nothing works at the moment.
Don’t trust anyone. If they’re not keeping logs, their cloud provider (if they use one) probably is.