very nice chart, I will study it. thanks.
I am not a linguistic, all my knowledge is from self-learning and a bit from my father who is related in Mandarin teaching but not research, so he know some conclusions agreed in the earlier time, not very latest. So here is something about the highlighted texts of yours that I can share (in the order):
1. Yue, I thought it is from old Chinese only because the region has been reached and incorporated by early Han dynasty, about the same time as Min (Fujian). So I made the guess. But, after you said it, I remember that oversea Chinese of Guangdong decent self styled as "Tang ren" as in 唐人街 (Tang dynasty) rather than "Han ren" of Han Dynasty. That does indicate Guangdong was incorporated during Tang, so the mass settlement by Tang, therefor middle Chinese.
(2) I agree "old Chinese being the first sinitic language introduced to the south". Because the there is only one Sinitic language that is Han Chinese. All other related languages are in the branch of "Tibetan Burman" group. There is no other language can be called Sinitic. As shown by your graph. Remember, all Chinese dialects are understandable by their written form (meaning >80% common in grammar, same way of thinking and composing in mind) even though the pronauciations are very different.
The graph apperantly is made by non-Chinese linguistists who make Chinese dialects as languages, making Chinese a language family rather than a single language.
It is important to note that in Chinese linguistic terms, phonology does not play a decisive role in defining language, it is the grammar. That is different from European linguistists who emphasize phhonology to the point that they define Danish, Swedish, Norwaigen and Islandic as different languages which in Chinese terms are the same language of different dialects because their grammar are >90% common and pronouciation is >90% common between Swedish and Norweigen, >60% (Danish to Swedish listeners), >80% if reversed. Same goes with Serbo-Croat languages (Serbian, Croation, Montenegrian, Slovanian) or Russian, Bylarusian and Ukranian. It is difference definition, that leads to different catagorization. There is no common ground in this, personal choice.
The positon of Hakka in the tree runs counter to my belief of Hakka being from middle Chinese, but rather from old Chinese through Chu (kingdom before Qin unification). The very reason Hakka is called "客家", literally the Guest Family, is because they are regarded as later comers by other Southern Chinese. That indicates that they has to reach south later than Guangdong and Fujian people, so no earlier than Tang.
Once again, I trust Chinese linguistic research than Europeans in Chinese research. After all who is better knowledged about Greeks than Greeks themselves? Besides, it is a study of human culture, so a preset mind and belief makes the fundation. Gray is white to people who is surrounded by darkness.
(3) It is very true, although Ling Nan was counqured by Qin, until Tang it was still very less populated by Han migrants, until Tang dynasty Ling Nan was still regarded as place for exile/bannish (发配岭南), pretty much like Heilongjian or Xinjiang in Qing dynasty (发配黑龙江给披甲人为奴, exiled to Heilongjiang to be slaves for the officers).
(4) I won't because dialect or family is terms used by linguistists who has fundamental disagreements of what constitute a language. Nothing there to agree or disagree.
However and once again, sharing similar vocabulary is not a defining character of language. There are many words sharing (both meaning and phonology) between very far apart languages, that does not make them related. Examples are Morden English has over 60% of its vocabulary being derived or directly imported from Latin and Greek, two distinct languages (even by Chinese standards). Same goes to Vietnamese, Korean and Japanese having even higher percentage??? of Chinese vocabulary, for exampel Japanese vocabulary is made of 1. Kango (Chinese word), 2. Wasei-Kango (Japanese made Chinese word 和制汉字) and native Japanese word.
So if the difference in vocabulary is used as an argument for language/dialect debate, I can't buy it.
[Edit],
I realized why you asked "
old Chinese being the first sinitic language introduced to the south?", that is apperantly relevant if one treat Chinese dilects as seperate languages as the graph did. The question would be irrelevant if one believe Chinese was and always is a single language.