Possibly the best place to start is with questions.
This is great information and I appreciate the ways you've thought this out.
I wanted to add something for folks who are considering alternative grading methods. Something I ran into was that a lot of my students (community college level) really felt like there was some kind of hidden pitfall or "gotcha" within my grading system. Many of my students had not had teachers or professors in their lives previously that had earned their trust, and they were used to the system working against them at every turn. So that is something that I think is worth knowing folks may run into (a lot of my students were marginalized). It just took a lot of time and care to earn their trust, but it was possible. Still, I wish I had understood that from the outset when I was getting ready to do alternative grading the first time.
And second: it is so much harder to do something different in an online, asynchronous environment because you just don't have the same opportunity to remind them verbally of what you're doing and why, and to get real time checks about how they are feeling about the system. There are also ways around that (and you make great notes about how teaching F2F vs hybrid vs online asynchronous are all different). But I just want to reiterate that: I think it's harder in a purely online, asynchronous class to fully communicate the differences and to really know how the students are interpreting what you've said unless you build in specific systems to do that.