I will write everything I know to you.
Tongliao and Horqin Mongolians are mainly short robes, vests and hats.
70% of Hulunbeier Mongolians migrated from Horqin,
Buryat Mongolians 10% are mainly Mongolian robes. Mongolian robes have burrs on the shoulders and the hats are triangular. The most important thing is that their language is very different from that of the local area. I've never seen fashion in clothes. Most of the grasslands are more traditional Mongolian robes, which are more beautiful and have some elements of Russian princess skirts.
Hu Ba Mongolians: They are also Hulunbeier Mongolians who migrated from outer Mongolia. Their clothes are traditional Mongolian robes, but the color is generally monochrome, not so gorgeous, but more suitable.
The Mongols in Xilin Gol grassland are the colorful Mongolian robes that we often see on TV.