oil based
Oil based primer is the best bridge between oil and latex paints. If oil based paints are not available in your area, a high adhesion acrylic primer over a well prepared surface will also work.
Yes you can. You can use either oil based or a water based. I prefer a water based myself.
In the past oil paints referred to either petroleum based paints or linseed based paints. Today in the USA petroleum based paints are no longer sold and it is difficult to find linseed based paints though they do exist with a small proportion of linseed oil. Alkyd paints are made with synthetic oil and are readily available and have come to be known as "oil" paint.
There are good reasons why ointments are oil based rather than water based. A water based ointment would wash away too easily. An oil based ointment stays put. A water based ointment could be washed away by sweat, where oil would remain.
paints based on oil
Yes, you can apply oil-based polyurethane over oil-based stain.
paints based on oil
Castile is olive oil based.
No, latex paint is water-based, not oil-based.
Acrylic paint is water-based, not oil-based or latex-based.
oil based
Yes, polyurethane is typically oil-based.
I am fairly certain that it is oil based. It is pretty easy to find that on google...
Yes. Clean and degloss the oil based paint, apply an oil based primer, then apply the water based paint.
Is the paint you're using water-based or oil-based?
The polyurethane being used is either oil-based or water-based.