Conversions aren't "earned" income, so you can't apply the foreign income tax exclusion to a Roth Conversion.
Even worse, income below the foreign earned income exclusion can't be counted as income for contributing to a Roth IRA. So if you earn below $103.5k, you can't contribute to a Roth IRA. And existing restrictions also remain in place: if you earn over $137k income you also can't contribute to a Roth IRA. So it's harder getting money into a Roth IRA when you have foreign income, rather than easier.