With a few clicks, you can play as almost any NPC in the game.
Why almost? Because NPCs with unplayable assets, like Sheogorath's beard, won't work that way.
In this example we'll take our favorite early source of income quest giver Glarthir.
There is a video version of this, if you prefer. This link will bring you to youtube.
1.) First, we open both the NPC we want to copy and the player char. The player is just called player and most NPCs have IDs matching their name.
2.) If the NPC is anything non-imperial, we'll select the matching race.
3.) In both windows, we will scroll to the tab "Face" and manually adjust the few settings here. Hair is a dropdown list and for the hair color you can just enter the numbers. As for the other values, they might change a bit after entering them, it doesn't really matter if a value is -0.9 or -0.89.
4.) Now the fun part: Switch to the tab "Face Advanced". On the NPC, we select Copy, and on the player, we select Paste.
Make sure to save your plugin and activate it, in a mod manager of your choice or in the game launcher's Data files.