can you tell me

1- can i choose to use polycrylic to seal my paint? I had waxed a step stool but found it marked easy and was maybe thin although I had 2 layers, I put a layer of poly on the steps to add wear but want to know for a big project. I put wax over my white and they went yellowish but it is ok however on my makeup vanity I want it to stay white

2- 2 layers show streaks but want an opaque look, should I do 3rd coat thinned with water or leave thick?

3- bleed thru.. the vanity was not mahogany but for some reason it leaches thru, i have put a coat of zinnser 123 as all available in my small town but still see the bleed thru, is this normal and the 123 dries clear showing thru but will hold fast?

4- table legs have 2 coats of white chalk paint and one of wax, is more wax needed to prevent chips and such to the paint?