I am not aware that Edge is "stupidly fast" on startup. Safari though, is indeed currently leading the field.
As you correctly outlined, V8 is indeed transitioning to a world with an interpreter+optimizing compiler only. If you are using Chrome Canary, there is a chance that you are already using the new pipeline :-).
Full disclosure: I work on the V8 team.
ECL and CLISP both settled on this model. CLISP started out as a bytecode interpreter and added GNU Lightning for native code generation. ECL started out as a source-to-source compiler to C and added a bytecode interpreter; both follow C calling convention as much as possible, at first for easy interop with C code and then for easy interop for the bytecode interpreter, which avoids the C++ interop problems mentioned in the talk.
How much of what's remaining is performance versus stability/correctness?
As for the Ignition+TurboFan setup, are you really that far along already?
Last I heard a few months ago it still sounded like it was gonna be a while before TurboFan was fast enough in most cases to be able to handle it.
If so that's awesome!