In areas i live, gujjars and ahirs are known to be related, also gujjars are slanged as milkman.These are very narrow regional interpretations; the Ahirs and Yadavs have better credentials (in western India only) as cowherds. Everyone is a farmer, not particularly the Jat. And the Rajput is born to battle, with or without the money; 'mercenary' has strong connections. Jats from the Sindh is quite possible; remember where the Sakas ruled? Rajputs talk about Mount Abu because the archetypical fire sacrifice took place there. Gujjars coming in much earlier is merely a memory of the phased, pulse nature of the incursions of this period.
Agree on Rajputs, mount abu is where i think agnivansha started.
A mere look on the population centre of these group can tell their migration order. Yadavas are concentrated in eastern up, gujjars are spread all over the place western up, kashmir, gujarat, rajasthan. Jats in punjab, haryana rajasthan and western up.
Mount abu is the place where the word rajput originated and brahmins gave them kshatriya status.As pointed out by Col. James Todd (the British Surveyor General of Rajasthan), the Sanskrit inscriptions (since sixth century AD) on ancient palaces, temples, forts etc. tell us that those buildings had been built by the Gujjars and not by the Rajputs (several supposedly 'Rajput' kings of medieval India were ethnic Gujjars in fact). Similarly,while the association of the Gujjars with the Mount Abu is noticed in many inscriptions and epigraphs, the association of Rajputs with Mount Abu is mostly 'legendary'. I believe archaeological studies and sources give a more accurate account of the past than literary or legendary history.