The mini access in Energy Portal which consists on 2 parts: first pulling 2 levers which last 10m, once done each member must kill 5 golden servant and 5 diamond servant in order to pass through the portal that bring you to levers, so is needed to complete all this within 10m otherwise the portal would close and no one would be able to go inside until the mini access is repeated (while those inside could leave whenever they want).
The mini access of Earth Portal is permanent, so you can access whenever u want after completing it which consist into bringing 3 parrots to the tree and fertilizing + watering 5 birchs in order to grow them, once done you can jump directly to the inside of the tree and subsequently to the lever always with no cd, the mini access of all other portals are pretty similar to Earth Portal since they are permanent and with no restrictions, except by Holy Portal and Death Portal,
Holy Portal consist into simply running through the place until you reach a time machine the difference is that once you use the time machine you end being teleported to a room with no mobs and unable to go back through a tp, so you must pull the lever and face the boss either defeat it or run away from the tp inside the boss to actually get out of its reign (which either way would end into boss cooldown).
Death Portal in the other hand require a Ghostsilver lantern Which can be found inside the room, it also require walk into specific tiles in a specific order which acts as taking the photo of a girl and bringing it back to the haunted old desk which would bring you access to the door, but in order to find and use this door you must have the ghostsilver lantern active at your bp, then actually you can go inside the room being the active lantern the only extra requirement.
Mini access for Fire Portal consist into talking with the father of Ivalisse, Silus who is disguised as A Strange Chalice inside the Temple Complex, once talking with him (following the marked dialogue) you will be able to go through the tp to a room filled with drakens which you can avoid in order to reach the portal that bring you to the lever room.
Ice Portal is pretty much similar to Fire Portal, consist into talking (following the dialogue) with A Dragon Mother under formorgar mines then walking directly to the lever room without any other restriction nor requirement.
While The Last Lore Keeper Portal (final boss) require to complete all the other portals in order to access but beside that have no other requirement beside walking to the tp to reach the lever room.
Source:
Tibiawiki Forgotten knowledge Quest
Personal Experience.