It seems you have changed your question and added more information that's very helpful to answering your question.
It seems clear that you do not provide more than 50% of the cost of providing a home for your parents or your children, so you would not meet the criteria to file as Head of Household for any qualifying person. Head of Household is different than support. You are required to be providing more than 50% of the household costs. These costs are related to providing and maintaining of the home itself.
You could file as single if you were divorced as of 12/31/2017.
