Like I said I have not tried this Daminion thing myself ... have no time atm (you can download trial). Once in awhile I will search net for this topic (been doing this several years). Yesterday stumble on this Daminion thing and this forum. Thought I would share this 🙂
1. It has version control (daminion.net/feature-tour/daminion-server/version-control). Regarding editing, I think it was not meant for just managing photos. Its main purpose is not just sharing, but managing and cataloging your digital files (including photo) so you can quickly find what you need among thousands files. For example search photo of me and my wife taken in France.
From what I gathered, editing is done outside Daminion. Have not try this, but I think it works something like this. Find what you want in Daminion. Daminion then gives you copy of file that you open with other program (like photoshop). Once finish editing you then give a new version to Daminion for storing (I think it keeps both new and old version of file). In a way this is more flexible as you can use different photo editing products.
2. Looks like it is only for Windows. For sure you need a separate Windows server to run its server side portion. Client side you use client app (for Windows only) or through web browser.
3. Access through web browser does not go through internet. Your web browser connects to your server (which is located at your home) through local LAN. So speed of your LAN is the limit, not speed of the internet. On possible downside you must test this on Safari (or whatever browser you using to check compatibility).
If you have time, try it (unfortunately atm I have no time for this). For my home use it fulfill most of my photo/video requirements (multi user access, cataloging, managing). Only thing is missing for me is light client for browsing cataloged photos/videos (something I can put on my iPad or HTPC or smart TV to show off my photos to guests ... imagined you can quickly show photos of you and your visiting friend on a trip several years ago quickly). But at least it has web client ... so can still access it from my iPad 🙂