Yep! If you send them shirts they'll sometimes put them on. Good luck!
What you can do is hold shirts in your inventory, have the villagers come to you, and they may ask to buy them or trade. They may wear the clothing that way - if it is a long while since they changed it. I don't think mailing works.
Another idea: Load the clothes shop display area with some of of your own designs you'd like them to wear. After a while, the villagers out of nowhere will wear them - though you have no control over which ones.
Out of all of them, three are wearing the same shirt, and another two are wearing the same shirt and its so....idk but it's weird :3 Maybe if I send them shirts they'll change?
I have the same problem, like 4 or 5 of them are wearing the same shirt, I mean I put a lot of patterns on display but no, they ALL had to choose the same one... I'll try walking around with t-shirts, this has to change, they're starting to look like a sect. x)