It is open. The only crucial canon that I'll "fight" over is Cindy was bitten by a spider under Reach captivity about 10 years ago. And Martin Li or Mister Negative is tied up with my plan.

Everything else is fairly open for interpretation and I can work with whatever.

Honestly a whole bunch of enhanced spiders being released upon the Reach's fall works. So anyone could have been bit at really any time.