dacsa79

Then if I'm reading the law right she is free to marry. 
 
edit to add 
you probably did this a few hundred times but just check the date it it take effect of. Mine says effective on this day blah blah blah. Which is the day the judge signed off on.

If you provided all the requested evidence in the petition, you'll be fine. 
In case the agent had some sort of doubt about that or any other document, you'd just receive a RFE.

In such a case, IF the divorce decree was not included, the petition would be incomplete, so the officer could request for evidence or deny.

We included the finalized divorce agreement and the certificate from the court. She is divorced and it's finalized with official signatures. 

I understand. As mentioned, it probably won't even come up. But just have the bill of sale handy during the interview. 
 
As with anything immigration, there is never the one thing that will tip the case over one way or the other. It's a bunch of things. If your case is solid, they won't even mention it. If you have 20 other red flags, they will throw it in there as one of them, and the combination of everything is what counts. 

Her concern is probably that immigration will say that the husband just fake divorce the wife and married her just for the GC to get to the US. Again, that is pretty far-fetched, if all they have is the apartment/condo.

The USCIS cares about you (both) legally being able to marry and that the petitioner has a clean background.  No one cares about your business in your home country.

The concern is whether USCIS will be suspicious of any appearance of remaining economically tied to her ex-husband.

Individuals who receive payments for child support are still "economically " tied to their ex.   Non issue. 

I mean, if you want peace of mind, yeah, translate the bill of sale and keep copies of it. I would not submit it with USCIS or NVC, but bring it to the interview just in case that even come up. 

Non-Issue........The primary concern is if the marriage has been dissolved.......nothing more.

I think it's much ado about nothing