That first one is for shooting around trees, at least that is what my grandfather told me for every crooked arrowhead I showed him.
Those bifurcates are fairly old points, and like many other groups in the Early Archaic period, they made specialized scraper/knife forms. Albany scraper by San Patrice makers, Edgefield by the Bolen makers, Red River knife by Scottsbluff makers. They might have had different uses, but at some point their tool kit became a lot less specialized than previous groups. Basically instead of having 50 different tools in the tool box like a Paleo person would, they showed up on the job with 4 or 5 and got it done.