House Sale Exemption and moving deductions

1) what all can be included as house costs to reduce my house sale gains that are above the exemption of 250K? 

2) are there any moving expenses that can be deducted?

3) my boyfriend and I both sold our own separate houses in 2021 and bought a new house together. If we got married before the end of the year, would we need to file married filing separately in order to each get our own 250K exemption on our house sales? 

4) are there deductions for any home repair or improvement projects we do on our house we just bought this year?