>>8096826>How hard would it be to add thigh swivels to this figure?Swivels are pretty simple. Pic related is how I usually do mine. It helps if you have a dremel to make the cut. For pegs I usually use the plastic from leftover model kit sprue trees or armature wire, as long as it's appropriately thick for the size of the figure.
When you drill, make sure you don't go too deep otherwise you will hit either the hip joint or the knee joint, but usually I try to make the peg half deeper so that there's plenty of glue and peg material in there so it sits solidly. And you want to make sure your holes are just barely bigger than your peg. If you do a test fit, they should have enough friction that they don't fall out but you can also turn it as well. If you make the holes too big, you can wrap the pegs in tape to add more friction.