Editing the manifest file of the SCORM package is NOT going to get you out of trouble if the SWFs in that package are not compatible with a Flash Player version below 10. If Captivate 7 is using tags or code inside the SWFs it creates that can only work on FP10 then your end users would NEED to have FP10.
Since Captivate 7 has only just been released, you cannot have gone too far down the road of developing this content. I would recommend you get this sorted out BEFORE you create mountains of content that your end users may not be able to view on their FP version. Upgrade an entire course to Captivate 7 format and test it thoroughly on end users from your company. If it turns out your content doesn't run perfectly, then you may need to roll back to Cp6x to continue with this client.