While anything's possible, her having the same hair and eye color as Wallace doesn't mean much of anything. Plenty of unrelated characters share the same hair and eye color (eespecially since hair color and eye color usually match)~
I know, like I said, it is possible since we don't know anything about her yet. But I just don't see them sharing hair and eye color as a very strong basis to suggest them possibly being related. It'd be like suggesting that Flannery and Maxie could be related.
It's just that I've seen this hypothesis many places elsewhere, as well, and I just wish there was some better reasoning behind a possible relation than just hair and eye color, which many characters share and aren't speculated as being related. Sorry, if I came across the wrong way with my original response.
It's fine. I definitely understand what you're saying, but the fact that Lisia and Wallace even have similar attire colors (not exactly the same, but pretty close) makes me think a bit. In the anime, Wallace was also a Top Coordinator, like Lisia is in ORAS. Speaking of which, I'm actually thinking Wallace may appear in the Contests with his Milotic in the Master Ranks, who has the potential to Mega Evolve.
I also have seen people speculating that Wallace may be involved in Contests (furthering the connection between the two), but I personally am seeing it as a bit unlikely considering his only connection with Contests is in the Anime and Manga and not so much the games. But, again, it is possible they could make him involved with Contests in ORAS.
The fact he's appeared in two other Pokémon media as a Coordinator means he may finally make an entrance as one in ORAS. I'm personally hoping for that, since Milotic's his main Pokémon and that's pretty much the poster child for Contests. I do really want Juan as a Gym Leader, since they could potentially make him more challenging by giving him a team of Relicanth/Lanturn/Crawdaunt/Walrein/Kingdra.
True, he could be a Coordinator in ORAS. I'm hoping they somehow work Juan into the story since they seem to be keeping things the same as RS and not taking make Emerald elements. I'm in the minority who would have liked to see him remain as Leader and have Wallace as the Champion, but since it's Steven, I'm worried about Juan.