The House can't vote for whomever they want. The House can only choose between the top three electoral vote recipients. There's no way the House can select Romney unless Romney gets at least one electoral vote, from a faithless elector, and nobody other than Trump and Clinton get electoral votes more than Romney.
But the House doesn't even com into play unless Trump loses 37 of his 306 electors. His *Republican* electors.
All the salty snowflake tears in the world can't make that happen. At most, a few politically-suicidal Trump electors defect - none of them to Clinton. He still has well over the 270 votes needed. She still has far fewer than needed, maybe even less than her supposed 232 because of the promise-to-be-faithless Clinton electors like WA's Satiacum.
Bernie Sanders is more likely to be the 3rd recipient of electoral votes than is Romney, if there even is any 3rd-place electoral recipient at all.
Trump wins. He already won, in the election that matters, the separately summed 51 states & DC elections to choose presidential electors. Nothing is changing that. Go put your efforts to some meaningful if you're progressive, like standing with Standing Rock, placing for the 2018 midterms, state legislator elections because that's where gerrymandering happens. Forward-looking stuff. Not this "Wah somebody better fix this" backward undo-it crying.
I really wish people would RTFM aka Constitution before putting out nonsense.