Exited to see these link-ups happening! 
Definitely agree with the importance of documentation to try and make efforts replicable; Autonomic is hoping to do more in this area as time allows.
Tech-wise, we tried and gave up with Ansible for app deployment. To add to our brief notes about our rationale in the Co-op Cloud FAQ, we found Ansible fragile as a front-end (several of us ended up in very cursed situations with our local Ansible set-ups, which were huge time-sinks to resolve), and found playbooks difficult to reuse between deployments, especially those coming from other groups.
I’ll also repeat here some comments from an e-mail thread about single sign on, which does seem like a key part of the puzzle tech-wise:
To explain: a key part of the idea behind cooperative.computer is that SSO-linked open source platforms are better than “everything apps”, even open source ones, because it lets app developers play to their strengths, and gives administrators freedom to experiment in choosing between them. We also see SSO as a killer feature vs proprietary systems which, if they support SSO at all, usually hide it behind an “enterprise” pricing tier, see https://sso.tax. So we’ve ruled out several great pieces of tech (notably Cryptpad, and email) unless and until they support OAuth or SAML.
We’ve started to explore the inter-group federation possibilities – git.coopcloud.tech supports (as well as some convenience corporate providers) logins with Autonomic’s Keycloak, and Local-IT’s (a Co-op Cloud federation member organisation) Authentik.