With accessories considered, no mixing lines (assume all characters are better than TMs)
Tenney is certainly helped by her special guitar/pin curl. I started collecting in early 2000s. I tried to remember the state of the brand/innovation when a new doll came out. Did not mix different brand lines other than GOTY/contemporary. Absolutely biased to what was cool in my eyes as a kid.
Credit to https://americangirl.fandom.com/wiki/American_Girl_Wiki for the images.
