You don't have to scrub that hard to remove the wax from the factory. It's an edible wax so just a good washing with soap and hot water will do. If there's a bit left, it won't hurt anything.
Newly seasoned cast iron will have a brownish tint to it. It's not rust, it's just a funny patina. It takes a few coats of seasoning and some use to get a black patina. Don't worry about the brown tint and just go ahead and use the pan. I don't know why it's brown. That's sort of strange because 'nekkid' cast iron is gray. Refurbished, used CI is black after seasoning, so maybe it has something to do with the seasoning being cooked into the pores of the metal over time or something. As I said, I really don't know.
Don't try to wash the seasoning off. You shouldn't be able to, for starters. Adding more layers is the best way to get a good patina, and you need not remove the layers in between unless the pan is rusty or the seasoning is rancid or otherwise something you wouldn't want to eat from. If you need to remove old seasoning, you can do so by running the piece through the self-clean cycle in your stove oven. It will need to be re-seasoned almost immediately to prevent it rusting. If it's rusty, the rust will have to be removed. I like to use an electrolysis bath for that, but since you have a new pan you shouldn't need to worry about that.
If you use animal fats to season CI, then be sure you use the pan a lot so it does not get rancid. There is nothing wrong with using bacon grease though. I use Camp Chef's Cast Iron Conditioner which works great, but it's not necessary. I have a lot of camp Dutch ovens which are used seasonally so they sit for long periods of time, so I prefer vegetable-based seasoning, but again, there's nothing wrong with animal-based seasoning.
I fire my CI at 400 degrees for an hour, and try to do so only in summer when I can open the windows. Then I turn the oven off and let it cool overnight without opening the door.
Don't expect seasoning to be like Teflon. However, keep in mind CI will heat much more evenly and brown things way better than any non-stick coated pan. Also, the seasoning on a CI piece is infinitely renewable unlike non-stick coatings, and there are no health risks unlike questionable coatings. A cast iron pan will outlive you, your children, and your grandchildren if properly cared for.