It looks like you might have some extra fabric in the border. Any pattern quilted along it is going to advance the fullness until you get a wrinkle. I would mark evenly spaced spots over the whole border. I would then use the bar tack feature on my Bernina to bar tack kind of like a tufted comforter. It looks like you have a nice puffy batt and the tufting would look real nice. As for the triangles, if you did the tufting, I would leave them off. Really cute and colourful quilt!