Also agree about 4 and 8. And pastels need to be over a flat coat. Unless that model will be handled, it is unlikely the pastel will come off if thoughly ground into the surface. A flat coat over pastels tend to lighten the effect so you will have to over do it and hope it lightens the right amount to get you intended end result. I always use pastels and never coat them when done.
EDIT: I just looked at the first post again, at the order of teps and want to just clarify soemthing. I use pastels to make a wash for the panel lines and base weathering. and that is done a #7 as in the list and thsi does get sealed. The last thing done, for me anyway is exhaust, gun blast, fuel/oil drips and some panel discoloing... after the last flat coat.