Well, in terms of any continuity, who is Button's father is likely going to be determined by Jan (of Jan Animations).
But, the fact the IDW comics introduced a video game-based pony that would be the same age-ish as Shining in the present, make him a prime candidate to use as head-canon for Button's father until we're told otherwise
Very nice work One thing that I might add, (and I have been noticing this for a while now) is that the front portion of a stallion's muzzle typically is represented with a thinner line (like here) . I'm aware that Ponyscape's power strokes do not like to cooperate with two settings of different width almost on top of each other. You can try a different technique to blend the stroke widths like Mutual Clipping but I suppose that is difficult to grasp if you've never used it before. However, other than that, this is amazing. Mind if I make a version with a background?
I have a time-lapse video you can watch if you want: youtu.be/M2-w2eUgn1U (I used vanilla Inkscape) I'm using essentially the same software but using very different techniques, to get a very similar result.
It's based on Inkscape but adds either existing plugins by default (such as the Power Stroke tool) and modifies a bit how some tasks are done that make it more friendly to drawing pony or similar cartoon-style artwork.