Hi. Welcome to the Briefing Room. Glad you found us and I think you will find that we are basically a very interesting group with vast personalities and passions. Mine happens to be the 2nd amendment and anti-illegal immigration.
Addressing your question(s). First, the GOP could very easily lose the House and if they do, I believe the first thing that they will try to do is impeach Pres. Trump. I doubt they will be successful, as the Senate will probably retain their majority. IMHO they will investigate other areas other than Russian collusion; probably Trump and his family's dealings with the Middle East and his tax returns. They will hound him and keep him busy defending himself rather than letting him lead this country.
If the GOP loses the House, we'll likely have 4 more years of Pelosi's hazy (at best) leadership. They hold the purse strings which almost guarantees no additional funding for Trump's promised wall. I believe that they will fight him on budgets and tax issues.
If the GOP loses both Houses; well, its game over. I think you will see President Trump impeached and asked to step down which will cause a huge disturbance among the populace. I also have absolutely know doubt that you will see a huge push for amnesty, which guarantees the liberal vote for decades and I think that they will try to unseat Kavanaugh. Along with that I think they will push to change the electoral college and term limits of our justices.
I also believe that should the GOP lose both Houses, Pres. Trump and don't manage to impeach him, he will still be a one term president. Not because he will have lost his voting base, but because the DEMS are so corrupt and will have manipulated the voting process and districts in their favor. Certainly they will have found a way to grant amnesty and register illegals to vote.