To move or not to move? (Sofia)

Hi All and apologies for the trivial Subject line but we are exactly at that crossroads right now. I have been living in the US for 15 years now but born and raised in Bulgaria. My husband is from the US, we have 2 kids of which one will be in 3rd grade in the fall.
With that being said, we have been considering moving back to Sofia to be closer to family and to expose our children to life different from the 'American dream' and its reality.

Schools: My son does not speak Bulgarian so we have to pick a school where all subjects are taught in English. Anglo American school is out of our budget so we are not even considering it. The remaining schools seem like they don't follow Common Core which is what the Am schools follow so I am concerned my son will get very confused?

DayCares: We'd like our daughter to attend all-english day care so she keeps her language skills up while picking up Bulgarian outside of it.

Work: This is another tough one. I think once we get passed the huge salary gap (and how little one's efforts are valued!), finding a job at an international company has proven hard for both me and my husband despite our degrees and experience here. Any idea why?

Housing: We have been researching places to rent and so far saw a few 3-bedroom apartments we like but their prices are pretty hefty too.

Moving: from US to BG seems like an huge effort in itself. How did you approach it?

Taxes: How do you pay into your SSN or such back in the US while living and working in Bulgaria? If we reach retirement age, we would be relying on US retirement and 401k but if we don't invest in it while working in BG what happens later on?

I'd appreciate anyone's feedback and advice!

Thank you!