Multisite, Cloudflare and memory limits

I know multisite in general works here, but I need a few things clarified.

1 - Cloudflare integration at one point didn’t work without www. Has this changed, or would multisite work if I installed it on and put all other sites on their own subdomain?

2 - Will Cloudflare, as integrated by Dreamhost, work with each site in the network, even if I have to set it up manually?

3 - Are memory limits set per domain or per subdomain? I seem to recall they are per-user, but in the case of multisite I guess I’m more specifically wondering if each Wordpress site within a network has its own user.

4 - What’s performance like on shared hosting? Are there appreciable differences from a single Wordpress install?

5 - Bonus: Does DreamPress support multisite?