Well a Kenobi-Satine route does not eliminate the possibility of Rey being a Skywalker, as any child of Kenobi's with Satine would be older than Luke, but not so much older at to make it weird or impossible biologically speaking. (One would have to determine if this child was born from their first encounters back when Obi-wan was a padawan, or during the Clone Wars, which doesn't seem to give her time to have a baby between her appearances.)
If it were up to me, I'd have the child be the product of that year Satine spent on the run with Obi Wan & Qui Gon. It would seem plausible that she wouldn't tell Kenobi about the child for two reasons; firstly out of respect for his dedication to the Jedi and not wanting to complicate things for him and secondly, given Mandalore's unstable political situation (they just had a civil war) and with Death Watch still lurking in the shadows it would have been safer for her child to be raised in secret, away from court. The irony being that in this situation, it's likely that her Death Watch sister would be the one to ultimately take up guardianship, probably getting him or her even further underground and as far away from Mandalore as possible.
The exact timing is unclear save that it was obviously before the events of TPM, which would mean when Satine died (which I think works out to less than a year prior to RotS) the child would have been at least 12 or 13 years old.
That alone would I think preclude any cross-marriage with the Skywalker line, even if it weren't for the "ick" factor or the mind boggling coincidence. Personally, I don't think Luke ever married or had children, so to me it's academic.
That age bracket would however make it perfectly plausible for Rey to be the granddaughter (or at a push, great-granddaughter) of Obi Wan & Satine.
Like I said though, that's a lot to have to explain to movie audiences so I doubt they'd go with it.
Has there been any suggestion that Jimmy Smits is in it???
None that I'm aware of, but then there was no hint of Genevieve O'Reilly returning as Mon Mothma until the trailer broke, so who knows?