Lol okay, everyone just settle down for a minute!
BV, I'd have to recommend you stay away from that store for a day or two...or longer
I can't even keep track anymore...tell me exactly what you have in this tank at the moment?
You need to give them a chance to settle in and get comfy. You're not going to get anywhere by constantly adding fish, returning fish, changing around fish, on a daily basis. For one thing, they won't show their true colours until they've had about a week to get comfy in their new home and change to their normal colours, instead of the stress colours you're seeing now. They are much easier to sex when they're showing normal colours, trust me
Honestly, leave 'em alone for a few days, lol. I know you're excited and want to get a pair, but its not something you can force upon them in a day or two. There are PLENTY of places for fish to hide and retreat if they're getting picked on, so unless you see them doing some serious damage to each other, just let them be and sort things out on their own, and THEN bring the other fish back to the store.