There are several songs in my repetiore that I practice daily and have seen great improvement since starting the program. I sing these songs from Youtube, with one headphone on (to hear my voice). I wonder, would it be better to practice the song just with piano or a backing track in order to make it my own? I notice that I tend to replicate the style of the singer, even including small ornamentations and vocal accent. I can get to sound quite a bit like them, but should I intstead be working towards singing the song in my own voice and style? I don't even know what style I am at this point, since I feel like I parrot so much. I have a bass voice and sing a lot of Johnny Cash, Avi Kaplan, and Josh Turner.

That's a great idea! Singing along with a karaoke or piano track, you'll have more freedom of expression. Please see here for some advice on finding your style: https://www.youtube.com/watch?v=DYByF2ORKzs