Is it necessary to use oil primer underneath oil paint (for trim) or can I use latex primer? Do all primers work interchangeably with oil and latex paints?
The rule of thumb is you can use latex paints over oil primers and latex primers. Do not use oil based paints over any surface currently coated with a latex primer or paint. The oil based paint or primer will usually lift the latex product and leave you with a wrinkled surface that looks like alligator skin.
It depends. Newer paints/primers hold up a lot better. You need to check the manufacturers website. The biggest issue you will have with a latex primer is that it will need to be pretty far in the curing process to paint over it - meaning it could be a month or two. Again you need to check the individual manufacturer's website.