Best way to get them to breed is a few simple steps to entice them. You can do alot for them to get to that point of breeding. It's like you getting your pair of friends ( male and female) to meet up. Take them to dinner, buy them a house and do everything butt do the act for them. Hehe
Here is...
They are being totally natural. They are doing a submitting wiggle and dance. The little guy is submitting to the larger one. So it's likely the are pairing up for you. Be careful of the 3rd wheel. They like to be in pairs. I would suggest removing the third one as it might get beat up and...
They will fight and one will die. Especially if the perc pair is an older pair they will kill the newbie in short order. They are pretty fish but can be very mean and territorial. Clowns are best kept as a pair. Best option is to sell the percs and get the skunk pair. If you want skunks. Or...