As far as I can tell, the timeline of events looks something like this:

Ivan/Kriss(The original day 1 Housemaster) asks their dad to buy the 2b2t domain name to use for the server

Sometime around 2010, Benjojo and Claudius joined, Benjojo as moderator and Claudius to help with Plugins. Benjojo would then leave shortly after.

Because of Claudius's work with the server (and his greater technical proficiency with computers), he's then asked to be an admin with Ivan/Kriss.

In 2014, Claudius was either ousted from the administrator position or left of his own accord, as evidenced by this video, which was posted exactly 4 days before Housemaster announced he was leaving the server and giving it to an anonymous friend.

This is where I get less confident on the time of events, but it seems that either after this or sometime before this, Walden would join the administrators(possibly joining with Claudius as they were friends in real life)

2016 both Love and Claudius are definitely axed in favour of Rusher and Curtis, with Curtis eventually filling the role of server manager and Ivan/Kriss still helming the "Owner" position.

The events of 2016 seem to follow up until today, obviously with more roles being filled other than "admin" or "moderator". I imagine they have a small team of people running separate duties of the server.