Hi Andrea
I think everything you describe can be acheived with ACP. However, ACP itself doesn't know how to turn on/off power supplies, etc. But I do know that quite a few ACP users have tackled that issue - there are 'web-enabled' power supplies available. I think Bob will be able to provide input here as this isn't something I've done.
One of the great things about ACP is the open architecture, so it's it's easy to write scripts to handle custom scenarios (like automated power-up, etc.). I suspect somebody here will be able to provide an example script that you could modify for your specific needs. For example, I've seen several custom startup/shutdown scripts posted.
To try and answer your specific question, yes, the ACP console app must be running on the server at the observatory before anybody can connect using the web interface. You could leave it running all the time or, alternatively, you could remote desktop to the server and star it (re-start it) if required. Once the console app is running you (and other users) would just access the observatory using any modern browser. The ACP browser interface provides everything you need - you don't need direct access to MaxIm DL, FocusMax, or anything else, you can control everything through ACP. You even get a handy preview of the latest image from the main camera and the guider
Again, Bob has experience of this but I think that you'd need some kind of local support person as there are bound to be times when the server needs rebooting, something physically needs adjusting on the scope, etc. ACP itself seems very robust indeed. I can't recall it ever crashing on me. And there's a huge amount of logic in ACP devoted to handling errors, re-trying targets, failing gracefully, etc. Watching ACP take over the guiding process is like magic!
Good luck - do let us know how you get on!
Russ
Russell Archer
LX200 ACF 12in, SXVR-H9, SX AO-LF, SX Lodestar, SX FW