MR Joe Jedi 616 Power Question - Voltage, Power Splitting

I think I have a handle on how I will be performing the install of a 616 board now after way too much reading on the TCSS forums. Let's just say that my job paid me today to learn how to do a saber conversion. I don't understand everything yet (which is to say I don't understand most things... but I think I know what I need to do.

So, question: The MR 616 board can take an absolute max of 4.5V, correct? But it doesn't necessarily need that right, it can be 3.6-4.5V IIRC? If I'm not powering the LED from the 616 board, using a Buckpuck to power the LED separately, then 3.7V from a 14500 should be more than enough to power the sound board, and maybe even accent LEDs?

So to do this idea, I would have to do 1 14500 to power the sound board in a separately wired battery holder, and two 14500s in another to power the LED, or whatever the proper amount is...

Once I get this all figured out, I'll begin building, and then hopefully, I'll be able to post some nice DIY stuff for all my fellow n00bs. Following and making DIYs are my specialty, guessing and checking... aren't.