Yes, I got it completely working. Basically this means I can once and for all get rid of Script Dragon...

Here's a complete instruction on what you have to do. And anyone feel free to make a standalone Follower Hotkey Mod based on this script, I'm to busy with my project.
Oh yeah, and don't forget this will only work with SKSE.
1. Make a quest that has start game enabled and priority 50. Higher priority makes the pressed key respond better, but don't put it to high
2. Make a new global variable (short, not constant), which represents the hotkey, get DXKeycodes over http://cs.elderscrolls.com/index.php/IsKeyPressed2, I'm using 20(t) for 'trade'
3. Go to the scripts tab on your quest and put in a new script, that looks like this:
Spoiler Scriptname FollowerHotkeyScript extends Quest GlobalVariable Property FollowerHotkeyTrade Auto; this is the global hotkey varaibleActor Property YourActorREF Auto; It's important that this is a reference not the actor itself, so this will only work on actors actually placed in the game world, usually all followers are unique and have a reference in the game worldActor Property YourActor2REF AutoFaction Property CurrentFollowerFaction Auto ; Defines if the follower is following youEvent OnInit() RegisterForUpdate(0.1)EndEventEvent OnUpdate() If (YourActorREF.GetFactionRank(CurrentFollowerFaction) >= 0) && Game.GetPlayer().GetDistance(YourActorREF) <= 500 && Input.IsKeyPressed(FollowerHotkeyTrade.GetValueInt()); This part says if your follower is following you, within distance of 500 game units and you press your hotkey... YourActorREF.OpenInventory(); ...your follower will open his/her inventory ElseIf (YourActor2REF.GetFactionRank(CurrentFollowerFaction) >= 0) && Game.GetPlayer().GetDistance(YourActor2REF) <= 500 && Input.IsKeyPressed(FollowerHotkeyTrade.GetValueInt()) YourActor2REF.OpenInventory() EndifEndEvent
Now you will have to do this for every actor that's a follower. Get a list of followers over http://www.uesp.net/wiki/Skyrim:Followers. You will also have to do this for commanding every follower and tell them to wait or follow. Exchange...
.OpenInventory()
...with...
.FollowerFollow(); to follow you.FollowerWait(); to wait for you.SetDoingFavor(); to command a follower
And just as I said, once you've done all that, the script will be huge, but it will also be working 100%...

Edit: Correction .FollowerFollow and .FollowerWait doesn't seem to work. I've also tried '.SetAv("WaitingForPlayer", 0)', but that didn't work either. Further investigations needed, though I'm also comfortable with only having command and trade hotkeys.