I don't think you're gonna find a chassis system for less than 700 or so, and the prices go up from there. Maybe a used one for a savage? which there aren't as many as the remington. Definitely buy the best optic you can afford.
Your list is actually in the same order as mine. Figured even though it'll look funny I can drop my sporter barreled action into the stock for the heavy barrel and still shoot it until I install the barrel. If you get an accutrigger model you might not even need to get a replacement trigger.
You can also look at the bell and carlson medalist, or the hs precision stocks. Aren't a chassis but do have an aluminum bedding block. Stockade gun stocks makes stocks for savages as well that have an aluminum skeleton.