Yeah I was going off that thread as well as the Pokewalker article on Bulbapedia
I figured that maybe something could be found, especially since team data for your trainer is also saved on the walker for the trainer's house.
Sadly I don't have the original save anymore which is why I wanted to see if I could get it off the walker.
From what I remember it was female around Lv. 20-23 with the ability Blaze (it's the starter one if that helps at all). There doesn't seem to be a nickname when looking at it in the Pokewalker so it likely just has the name マグマラシ but it could also have the nickname フレイム, the OT is ぎんが, male. Since I only made it to Violet City on this file the party likely only had some basic Pokemon like Pidgey, Sentret, and Ratata. That's kinda the extent of the info I have (〒▽〒)
Thanks for taking a look to begin with though, really appreciate it.