Any ways to smoothly change a players character?

I am trying to make a game based off of the anime "Shingeki no Kyojin". I have rigged models of some of their characters and I am trying to make a dev panel where you can turn into them. It works but with some bugs.

I don't know any other way to change the player's character other than using

player.Character = rig

It changes the camera angle and disables all guis as shown in this streamable

I know its possible to change the player's character smoothly because of this video

And if you're wondering, i made the nametag because i wanted it to be similar to the video and the hair model i had was a free model.

It looks like in their video they are only changing their clothes, hair, hats, etc. Have you tried saving the camera's current CFrame, then once the character is changed, you can set the camera's CFrame to the first CFrame? Kind of like this

local cameraCFrame = workspace.CurrentCamera.CFrame
player.Character = MyCharacter
workspace.CurrentCamera.CFrame = cameraCFrame

Apologies, I'm unsure how to fix the second problem.