Here is how the CARES ACT reads:
‘‘SEC. 6428. 2020 RECOVERY REBATES FOR INDIVIDUALS.
IN GENERAL.—In the case of an eligible individual, there shall be allowed as a credit against the tax
imposed by subtitle A for the first taxable year beginning in 2020 an amount equal to the sum of—
‘‘(1) $1,200 ($2,400 in the case of eligible individuals filing a joint return)
‘‘(2) an amount equal to the product of $500 multiplied by the number of qualifying children
(within the meaning of section 24(c)) of the taxpayer.
it states that an "individual" receives the $1200 - so whether you file 'single' or 'married-separate', you are still an 'individual' - TT could have better set up the verbiage to ask whether you filed 'individually' (which would include 'single' or 'married-separate') or 'joint' - because those are the only two categories that matter.
