Is the book "Truce at Bakura" going to influence Episode 7 at all?

Not even a little bit.

I think Disney declared EU novels to be non-canon, so I doubt it. Given the Ssi-Ruuk's (spelling off the top of my head there) penchant for Doctor-Who-meets-Lovecraftian-Mi-Go-mind-corrupting shenanigans, I reckon that's for the best.

Even though I'm a big fan of the Ssi-ruu and I enjoyed that book, I don't think there's any chance we'll see that story reflected in the new films.

I don't want new movies set 40 years after Return of the Jedi to have to reconcile 40 years worth of Star Wars stories. That would be horrible. Let the movies tell brand new stories with brand new characters; don't try to shoehorn Mara Jade and Grand Admiral Thrawn into the new films just because you like the characters, because they won't be the same.

I'm fine with multiple canons and continuities in Star Wars. I don't mind that all of the books and comics that came before are now considered a separate, alternate universe. Half of those stories were pretty bad anyway, so I make up my own timeline.

Given the Ssi-Ruuk's (spelling off the top of my head there)

Ssi-ruuk (singular noun)

Ssi-ruu (plural noun)

Ssi-ruuvi (adjective)

EDIT: Wait... I may have the singular/plural forms reversed... ?

TaB is probably toast. Disney/Lucasfilm did the canon wipe specifically to get the Star Wars timeline out from under the pile of novels that have come out between Jedi and now. Its possible we'll seem some stuff reintroduced, but its more likely to be gear, craft, locations, and personalities over family members and big story arcs (about soul eating lizards or not).

about soul eating lizards or not

Hm... sounds crazy when you say it.

Doesn't it though?

Yeah I seriously doubt there will be any mention of the Ssi-ruu much like there is almost no chance of the Vong or the Yevetha appearing. The Ssi-ruu were key parts of two novels and mentioned a few times in other novels and reference books. If any of the three appear it would probably be the Yevetha since their tech is closer to Star Wars norms than the others but e odds are still basically zero IMO.