Is it possible to animate 2 rigs at once?

If it's not possible then is there any methods to make this easier?

When you close the animation editor plugin, the current rig's pose returns to normal and so you when you animate the second rig, won't have any clues to what the other rig's pose looks like. Thinking about is already annoying

Yes it is possible to animate two rigs at once, however, you will have to load their animations separately in order to do so.

For this example, I will be using two NPCs (these can be swapped out for parts with AnimationControllers if needed)

local animation = Instance.new("Animation", game.ReplicatedStorage)
animation.AnimationId = "rbxassetid://0"

local animPlayer1 = workspace.NPC1.Humanoid:LoadAnimation(animation)
local animPlayer2 = workspace.NPC2.Humanoid:LoadAnimation(animation)

animPlayer1.Looped = true
animPlayer2.Looped = true

-- Available Events

animPlayer1:Play()
animPlayer2:Play()

animPlayer1:Stop()
animPlayer2:Stop()

You must own the assetId of the animation in order for it to be registered. The .Looped is optional

The :Play() and :Stop() events can be used to make the animations work at the same time or at separate times, they should be in the same script, but do not have to be in the same function.