#2. Am I on the right path of understanding the connection between Sakkaya ditthi and Anatta? I know there’s more learning/details to be done, but this is what I can realize for now.
If you haven’t read it, here is a recent post that addressed sakkaya ditthi and anatta.
About breath meditation, I used to do quite a bit of it, just like you. Some teachers of breath meditation (which they take as anapanasati) do say that it can take one to liberation since it’s a means to realize anatta (taken as “no self”). I haven’t heard of one who connects breath meditation to sakkaya ditthi.
The connection to anatta goes something like this: there comes a stage when one realizes that breathing is just breathing. There is no “I” who breathes; the “I” is an illusion, a mental concoction. Seeing through this is seeing anatta.