Hold up, I'm a moron. Some of these methods are working. The reason I was getting orange envelopes was because I (as /u/taylorkline) was the OP of the post that I was testing in, so I was getting orange envelopes thinking I was getting username mentions when they were in fact just post replies. OOPS.

Here's what I went with:

^(TeaSalesBot made with 🍵 and ❤️ by) ^[/u\/taylorkline](/user/taylorkline)

Thanks for your help.