a HSA is a savings account set up exclusively for paying the qualified medical expenses of the account beneficiary (your daughter). it would seem she has no spouse or dependents so only her medical expenses would be qualified if she was qualified to have an HSA. Based on the rules below she is not eligible for 2019.
to be an eligible individual to have an HSA all these test must be met
1) must be covered under a high deductible health plan (HDHP)
2) may not be cover under a non HDHP (coverage by an FSA is considered coverage by such a plan - so she can not contribute to her HSA while covered by your FSA)
3) can't be claimed as a dependent on another's return. even though she is 25, she could be eligible to be claimed on your return as a qualifying relative.
here are the tests. if any one is failed she is not a qualifying relative.
1) meets relationship test (same as for qualifying child) - she meets this test
2) gross income for 2019 less than $4,200
3) you provides over ½ her support
there is a last month rule, which would have allowed her to contribute to her HSA for all of 2019 provided she was not covered by non_HDHP on 12/1/2019.
i conclude she is not eligible for an HSA in 2019
for her to be eligible for 2019 you need to drop your coverage of her before 12/1/2020, it really makes no sense for you and her to have medical insurance for her. most policies provide for coordination of benefits when there are multiple policies covering the same individual
