I don't think it would be an issue as far as the marriage goes, but if it were me, I'd get married well in advance. As long as you have proof of marriage, such as a marriage certificate from the state, you should be good to go. As a matter of fact, marriage cert is required.
As far as the paystubs go, or lack of it thereof, perhaps you could get your fiancee's employer to issue a letter explaining the gap, such as, perhaps she was on vacation(?) A gap in employment on a H1 isnt usually a good thing unless you can prove the reason. Was she out of the country? Was she unable to work due to circumstances? Was she unable to work because she was out of a project (if she is a consultant?)...my point is, you need to be abl e to answer these questions...else you'd end up with an RFE.
Just curious...is her employer not doing her labor? Is that why you're going down the CC route? I mean, if her PD is current, which since you're using CC, I assume it is, then why not just get her to file the GC and have you be the spousal beneficiary as a secondary applicant?
.. Hopefully, you would have filed and gotten your GC by then and wouldn't be extending..