Originally filed tax return where there was a refund. I was then told after the fact and I had asked prior to filing, there was a 1099R for $52,000 from a 401K. Purpose to purchase first-time home. This gave a total taxable income of $ 182,000  with additional tax due $15,900.  Due to the $150K threshold they lost $3400 in child credits.  

If file separately:

Person A's total income is $142,000  $52,000 came from 401K for the purpose of first time homebuyer.  Person A  The tax liability is $16,836. This child in question, belongs to Person B

Person B total income is $47,504 from Social Security.  The tax liability is $763. However, since he did not have the child last year, I believe he would be allowed the $1400 stimulus and the $3000 child credit giving him a refund of $3,637. 

By filing separately the actual tax liability would be $13,199 or saving $2700.  Is this correct?