this paper attempts to argue that the edicts of ashoka were actually based on the delphic maxims, which have apparently been found in the region in tablets dating back to 300 bce (about 40 years before the first known fragment of the edicts).

the texts i've read on the indo-greeks have stressed that there was a black hole in the historical record in terms of understanding the exact greek influence on buddhism, but they would be fairly old and it appears out of date at this point.

i did not realize that there were concrete proposals for a genealogical link, based on actual archaeological findings; this theory appears to have advanced quite a bit since the last time i looked into it.

https://www.persee.fr/docAsPDF/dha_0755-7256_1990_num_16_1_1467.pdf

this paper makes a similar point, if you can't read french, without being explicit:
http://www.singor.org/publ/singor201201.pdf