Must one make up for days of Ramadan that a Muslim fasted while hesitant about the definitive intention to fast from the night, and if making up is obligatory, what is the ruling for one who cannot find a way to feed a poor person?

The matter of intention (niyyah) is easy. Whenever it crosses the mind of a fasting person that they will fast tomorrow, at any part of the night, they have made the intention. The certainty in the intention for fasting is the resolve without hesitation. Doubt about the certainty of the intention affects the validity of the fast, so it is necessary to ensure that the intention has been made correctly, because the default is its absence until it is proven with certainty.

However, doubt about the intention or its certainty after the fast has been completed does not affect it, and your fast is sufficient.

As for one who owes compensatory fasts for Ramadan, they must fast them. Feeding the poor is not sufficient for them, even if the days are many, unless they are afflicted with a chronic illness from which recovery is not expected. In such a case, expiation (fidyah) for each day is sufficient for them.