I can see the two being more "distinctively" far south Chinese but I'm not sure at this point if they are necessarily more native than the other guy. 

imgur.com/a/KV1itnt

Both of the male athletes from the Laotian olympic team in 2020. For some reason, Laos seems to have a higher rate of these types than NW Thailand?

Liangdao???

Liangdao and Austronesian should not be placed in the same sentence… if you can’t figure out why this is, you shouldn’t be speaking on the subject of Austronesians.

BTW the Liangdao skulls are morphologically quite similar to a specific Yayoi skull type I have found, which might correlate to certain modern Fujianese phenos.

Liangdao and modern Austronesian samples are indeed clustered very close together on PCA charts, to deny this is tantamount to lying.

Plus the Liangdao samples have mt-haplogroups R9 and E, both are fairly common among modern Austronesians.

And I've never heard anything about Liangdao skulls resembling Yayoi ones.

“Northern shifted” phenos like these are actually fairly common among Filipino-Americans, which align with bulk Taiwanese aborigines

imgur.com/a/AWwNcIh

Even more “southern shifted”/visibly Onge-shifted phenos like this have a distinct Austronesian skull/eye shape

imgur.com/a/vDbO0Cz

Which, if you look closely is in the direction of certain Jiangsu or even Shandong people

There’s a bunch of these big cheekbone pseudo-Mongol types if you zoom in to your second and third pics

Btw if you want to search for pics of Northern Thais online by your own means, I surmise anwyhere from Chiang Rai to as west as Mae Hong Son or down south as far northern parts of Sukhothai and Uttaradit aka former Lanna Kingdom (except Chiang Mai city, the other districts of the Chiang Mai Province should be fine as there should be less migrants than the main district/city area). But keep in mind, many of pics you see online might be hill tribe minorities rather than the main Northern Thai/Khon Mueang group (although it can get complicated as there are many other Tai-Kadai minorities in the North such as Tai Lue, Yong, Khuen, Shan/Tai Yai as well).
 
If you travel south of that specific region to Phitsanulok and central, southern parts of Uttaradit and Sukhothai and downwards, the general populace will have darker skin and look much more Austroasiatic similar to Central-Eastern Thais and Southen Isaan locals. Only exception is several parts of Tak Province, which is located more west than north including Umphang (southernmost district) as there were historical migrations from Northern region. So a lot there are actually Northern Thai by origin and look as such despite not being geographically located in the north.

When I was traveling with my family in Nan Province, I was shocked by the amount of overlap in phenotypes of the folks there and the Vietnamese. But later when we are returning home passing through Phitsanulok, I noticed the locals immediately look more like your generic tanned browner Siamese/Central-Eastern Thais, Khmers, Mons. Phitsanulok locals also speak a dialect of Central Thai and practice similar culture to Siamese/Central Thai rather than Northern Thailand, which has a different dialect/language and culture.

Here is a map of the provinces btw:


upload.wikimedia.org/wikipedia/commons/thumb/c/c5/Thailand_provinces_en.svg/1050px-Thailand_provinces_en.svg.png