Multiple state tax returns with foreign non resident income

I am having a bit of an issue trying to figure out the proper state tax returns to file for 2020 tax returns and in what order.

I lived in the Netherlands with foreign income up until Feb 16, 2020 (flew home due to covid lockdowns).  Worked for the foreign company from the US up until taking a job with a US company based in Massachusetts on April 18,  but working from Georgia.  Bought a house in New Hampshire to work at that Massachusetts job - never lived in Massachusetts.  I have rental properties in Georgia.   It seems like MA requires state tax returns to be filed there regardless of whether you ever lived in the state.  New Hampshire has no state tax.  Georgia taxes are required due to rentals there.  Which state gets to tax my foreign income which should not be taxed at all because there is a foreign tax treaty, but somehow it looks like everyone wants a piece of the pie.

Also, I bought a cabin in N. GA that needed rehab.  I tried to enter it as a rental property but since it did not receive any rent for the year but had lots of rehab expenses, it was not a sch E property.  Where do I enter this?   Is it a sch C biz until it is done being fixed and rentable?