1---Tapered and a parallel for a Recurve
2--Think of a selfbow with longer fades 2-1/2 to 3", so a 1pice recurve with a 16" Riser would have a strip 1/8" thick or so 18" long glued on top and tapered out past you riser fades, making your riser longer.
3--Butt wedge ( the triangle thing) for a Take Down it is the same as your fades on a self bow, to keep it from breaking at the end of the T/D riser
4---Action wood is bamboo vertical flooring cut into lams, same as a Osage (vertical grain) backed bow, it's stiffer (action)
https://www.ambientbp.com/classic-solid-bamboo-flooring.php5--- Glass and lams, all 1-3/4 wide for glue up, finished down to 1.6 wide or so at the fades and 5/8" at the nock