On raw fibreglass, epoxy primer is necessary. On gelcoat, polyurathane paint sticks well, provided the surface is well sanded and cleaned with acetone, but pinholes and cratering can be a problem, so where a high standard is required, priming the gelcoat with epoxy is recommended.
Almost any kind, including epoxy enamel.
To prevent staining over epoxy when working on a project, ensure the surface is clean and dry before applying the epoxy. Use a primer or sealant to create a barrier between the surface and the epoxy. Additionally, avoid placing items that may cause staining, such as food or beverages, on the epoxy surface.
Yes, you can use polyurethane over epoxy for your project.
Not directly. You will need to use a primer made to adhere to oil and will accept a latex topcoat.
Yes, you can use polyurethane over epoxy for a protective finish.
You can definitely use latex paint over epoxy. In fact, it is recommended to use latex over epoxy by the paint manufacturers, rather than using epoxy over epoxy. The latex adheres better and if you then want to use epoxy next time you paint, you have a nice coat of latex between the layers. If you use epoxy over epoxy, often the paint will just peel off in layers once some time passes (and sometimes right away).
you only use primer over bare wood or stains. If you have really tough stains you might need to use shellac based primer, otherwise any stain covering primer.
Yes there are certain kinds of epoxies that can be applied over SOME sealed floors. It depends on what type of sealer was used first. They tend to not bond well with some solvent sealers, but water based ones will work. You just have to use the right epoxy primer so it will bond
Start with a primer, Perma Seal is great. then I would use oil based paint.
Latex.
I would use Kilz latex primer.