There is something we are missing and the media are missing. The Russian lawyer went to Trump Jr. supposedly having dirt on Hillary. There was no dirt and the meeting was totally legal. This meeting in all probability was the basis for the FISA warrants and wire tapping of Donald Trump and associates.
The lawyer has connections to the Democrats and the Russian government.
It is my belief that Comey or some other creature of the swamp sent her to meet Trump Jr. in an effort to get the FISA warrant approved.
From press accounts I've read you are correct. We know now the Russian lawyer had a "probation visa" issued by the State Department and should have been long gone after completing her "visa business" on behalf of her Russian client. I'd like to see an INS explanation of how she hung around after the visa expired. I ditto your assumption this staged lawyer visit might have been used for further FISA requests.