Looking real good.
I had the same experience with the hole saw on MDF.
I found it does a lot better if you drill a bit, then pull the hole saw out to let it sling the dust off. then go in again. Very time consuming.
I definitely use the paddle bit for small holes such as the buttons.
The paddle bit works much better than a twist bit on real small holes too.
I have a black & decker kit of paddle bits. 1/2 inch through 2 inch bits.
Very handy tools. Gets used a lot on my hobbies and my around the house projects.
Good luck with your project, and I like the picture of wolverine (I think) in the background.