This could work. There were three clones-One of Gwen that was hypnotized to have sex with Norman and believe that she was pregnant. (Good. It gets rid of the out of characterness of Gwen having sex with Norman, it gets rid of her saying she did it because of his magnetism-since when has he been portrayed as a chick magnet?-and it explains why Gwen never told Peter) and Sarah and Gabriel would be clones of Gwen and Peter, which would explain why the son of Gwen Stacy and Norman Osborne would look like Peter Parker. The drawback: Someone might say "Hey, as long as we have a Gwen clone while she was still alive, why don't we make it the Gwen clone that was killed."
After Norman was killed, the Jackal created a Norman clone and orchestrated his rise to power because it's a lot safer to be the unknown guy pulling the strings of a puppet that it is to be the guy out front who takes the heat if anything goes wrong.
Now, the marriage. That was a May clone who was dying. The Jackal hypnotized Peter and Mary Jane into thinking they were dealing with Mephisto. All he did was replace the clone with the real May, who was never dying. When they discover that, they're released from the post-hypnotic suggestion that they were never married. (Their immediate circle of friends was under a similar suggestion, except Harry who, of course, is also a clone.)
There's probably a dozen things wrong with that scenario, but you could say the same thing about Sins Past and OMD, and they got published.