Thanks for those great points.
We can throw in another: Endurance running which is associated either with a scavenging lifestyle or with running down prey until they collapse with heat exhaustion. While Homo habilis had some of the necessary characteristics, a much fuller set are present in H. erectus. (http://www.clas.ufl.edu/users/krigbaum/proseminar/Bramble_Leib_2004_nature.pdf). This is suggestive that in H. erectus meat (or large animal fat and meat) were increasingly important food sources.
It's worth laying out a time line here:
~2mya, Homo habilis: Diet was mainly vegetarian but likely included insects, small animals and possibly a very small amount of meat (c.f. chimpanzees who's diet include 5% meat)
1.8mya->300kya, Homo erectus: Evidence scavenging mammal long bones and cracking them open for marrow. First evidence for controlled fire and cooking at 1mya. Strong evidence for endurance running.
~600-200kya, Homo heidelbergensis: Strong evidence for cooking. First evidence for symbolic thought .
~300-30kya, Homo neanderthalis: Enlarged hyperglossal nerve, anatomically similar hyoid, modern FOXP2 allele, strong evidence for symbolic thought; this is strong evidence for language.