I have done some bodywork in the past from bare metal to finishing coats. Usually you want to use the same system from etch to top coat, to avoid any trouble along the way.
The phosphoric acid in the etch primer can cause both polyester and epoxy products to not harden fully. Since some of those hardeners are sensitive to acidic surfaces.
I would not use soap and water to clean the etch primer before paint. Use thinner carefully if oil or grease or something has hit the surface. Otherwise just clean rags and spirits that doesn't leave any debree.
Just be aware that you will need to do a lot of sanding with long block, filler, sanding, polyester fille pr, sanding etc. to achieve straightness. If you are really serious you should apply the base coat, filler, polyester and then when sanded straight, add a layer of epoxy primer and let everything "sink" during a couple of months before sanding it down lightly and applying the top coats.
Are you planning to build a temporary paint box with some wood, plastic coverage and a kitchen fan or so sucking out the fumes at above the car? Or will you have access to a real paint box?
I have tried both. One time I used a small garage that I had and just sprayed water on the floor before applying the top coat to bind the dust.
Wet sanding and rubbing the final paint a year or two after it was done can make wonders aswell.
w460.333 1982 Colorado Beige 300 GD OM617.931