First,tell whoever is touching your car to quit touching it ctfgt.You're definitely going to have to re-sand the areas of surface rust.Where ever you see any surface rust(look with a microscope,if you don't get it all it will come back to haunt you).There is alot of products out for metal prep but what i would suggest is if your paying this guy good money to do this ,i would contact him and ask him what he wants you to use.Better off though you/he should prep the metal as close as spraying it as possible.The reason i tell you to contact him is because if something goes wrong i wouldn't want to see you get blamed for "the product you decided to use" and end up paying more money to fix the problem.If he uses his products and screws it up it's on him.I would suggest however if he is doing it in your garage make sure you have any silicon based items such as(moulding dressing,tire shine,etc etc,just read the label)to make sure the lids are on and they are a far away as possible.They cause fish eyes.It's been a few years since i've been in the biz so i don't know all the up and coming products.ELDUBB440 will probably give you a shout,i do believe he used to be a jobber.Hell back in the day i just sanded to bare metal,wet it down with Enamel reducer (3812)or laquer thinner and then went behind it with a dry rag and went ot spray'n.Never had no issues.But,things are chang'n.Hope this helps.
carl