This isn't a revived Steve Trevor - I think we can all agree on that, no? If Steve Trevor (the original) is alive here, then he'd be alive for BvS & JL; which he wasn't. This isn't going to be a descendant either, cause Diana is unlikely to fall in love with the same guy(?) twice, and this inevitably leads into BvS & JL.
I'm guessing it's either someone else in disguise (someone who doesn't know about Diana & the Amazonians), or someone/thing has revived Steve, but he'll die by the end of it (again); the latter would undoubtedly irritate me cause it'll just feel like a recycled plot, but I guess we'll see.