Zipper fly: https://blog.fabrics-store.com/2020/07/26/sewing-glossary-how-to-sew-a-zipper-fly/
zipper fly tutorial
Zip by hand: https://sewingontheedge.blogspot.com/2018/07/how-to-set-in-zipper-by-hand.html
Lapped zipper: http://malepatternboldness.blogspot.com/2016/02/ladies-tailoring-lets-make-lapped-zipper.html
Sleeve placket: https://blog.fabrics-store.com/2020/10/01/fs-lily-dress-pattern-sewalong/
Barbara emodi low-stress placket method: https://sewingontheedge.blogspot.com/2014/12/sewing-shirt-placket.html (if you trimmed the fashion fabric SA before turning the placket, or just cut the placket wider and wrapped it around the fashion fabric, could you do this on a stiff body fabric that doesn’t want to be more than one layer? IE quilted fabric)
to the touch 