Hi Shelia,
If using the intumescent paint the frames should be included. Covering over previous paint is not ideal and you would need to know what type of paint was previously used.
Generally it is three coats and will need to be certified by an engineer or by the supplier company and the certificate submitted as part of the fire safety certificate application. You might want to check with a fire safety engineer as the doors may already offer 30 minutes protection and need minimal work. Georgian houses in Dublin were originally fitted with solid oak doors and these should easily achieve 30 minutes.
Kevin