How would I go about this script?

respawn_time = .01

allow_force_respawn = false

force_respawn = "rspwn"

--------------------------------------------

game.Players.CharacterAutoLoads = false

function onPlayerDied(player, character)
	wait(respawn_time)
	player:LoadCharacter()
	PlrPlrs = player.Name
	PlrWrkspac = game.Workspace:FindFirstChild("PlrPlrs")
	wait(1)
	if game.Workspace.StageNum.Value == 1 then
		PlrWrkspac:MoveTo(game.Workspace.S1Spawn.Position)
		elseif game.Workspace.StageNum.Value == 2 then
			PlrWrkspac:MoveTo(game.Workspace.S2Spawn.Position)			
	end
	end

function onPlayerSpawned(player, character)
	while not character:FindFirstChild("Humanoid") do wait() end
	character.Humanoid.Died:connect(function () onPlayerDied(player, character) end)
end

function onPlayerChatted(player, message, recipient)
	if message == force_respawn and allow_force_respawn then
		player:LoadCharacter()
	end
end

function onPlayerEntered(player)

	player.CharacterAdded:connect(function (char) onPlayerSpawned(player, char) end)
	player.Chatted:connect(function (msg, rec) onPlayerChatted(player, msg, rec) end)

	player:LoadCharacter()
end

game.Players.PlayerAdded:connect(onPlayerEntered)

How would I go about moving the Player to the stage spawns after they respawn?

function onPlayerDied(player)
    wait(respawn_time)
    player:LoadCharacter()
    wait() --Give the Character a moment to load.
    PlrWrkspac = player.Character
    wait(1)
    if game.Workspace.StageNum.Value == 1 then
        PlrWrkspac:MoveTo(game.Workspace.S1Spawn.Position + Vector3.new(0, 2.5))
    elseif game.Workspace.StageNum.Value == 2 then
        PlrWrkspac:MoveTo(game.Workspace.S2Spawn.Position + Vector3.new(0, 2.5))          
    end
end

 function onPlayerSpawned(player, character)
    character:WaitForChild("Humanoid")
    character.Humanoid.Died:connect(function () onPlayerDied(player) end)
end

The first function included your error. Basically, you were searching the Workspace for "PlrPlrs", not the string in the variable itself. Also, you don't need to do that, since you already have access to the Player object. I added some height to the MoveTo's target position so the Character doesn't get stuck inside the SpawnLocation.

For the second, I removed the busywait, and removed the second parameter from the onPlayerDied call, since it is never used.