I could do it...
You see, doing it for Matt would be easy. Doing it for myself though... I'd want to get a 2nd Dannik, pop the head, fill the holes, mold it, cast it in proper color(s) and then paint it all up...
So yeah, I doubt it'd happen in MY style, but if you want the holes filled with something, Matt, and then them painted over... That's simple.
BTW I'd fill them with 2-part epoxy or something. Devcon plastic welder woudl be better I think... More durable, more plastic-like.
Personally, I'm likely just gonna leave my Dannik alone... It's **** looking, but I'm happy just to get him and the EU feature's "eh" to me. Kinda neat, but I'll just deal with the holes... It's the figures only real drawback though to me... Maybe the elbows too, but the face is the only thing that bugs me.