
You do realise that it wasn't a good idea to mate her more than twice - now you won't know what her due date is, other than within that time-frame.
My feelings about scanning have been posted before, so suffice to say, as I always did, it's a waiting game. By 7 weeks you should see puppies moving around unless she's keeping her condition secret (tucked up under the ribcage) to the last moment. Just to add, regardless of your plans (when we did a litter, we cleared all other activities until we knew what the situation was - well past the due date with zip), I'd bet even if you've been told nothing there, you'll still be watching

A scan only tells you the situation at the time of the scan. Not that she'll necessarily carry to term. X-ray a couple of days after the due date, will confirm the situation.
ps Letting your own dog near her until she was out of season - brilliant! Not. If by chance he did the job, you won't know which puppy came from which male - unless you DNA test each puppy!!!