My grandfather escaped to Taiwan with the KMT in 1949 and I'm curious about historical details around his journey, before, during, and after. I have stories that my mom has told me, but I don't know how much have been embellished. Some details I'm curious about:

1. My mom said that my grandfather was "snatched up" to join the KMT (she said 他被抓到). Was this part of a practice of recruitment? My grandpa was the only one in his entire family to go to Taiwan, so I'm assuming he was the only one who was in the KMT army (and he had at least one brother who joined the CPC). I don't know if he was an officer or anything like that, and I don't know when he joined.
2. He was from Qufu, Shandong. Since that's more northern, does that mean he joined the KMT earlier on and was with them as they were pushed south? Was there a difference between provinces (or geographic regions) in who joined the KMT vs CPC?
3. What might've the journey from mainland China to Taiwan been like? From this previous question about 1949, /u/AsiaExpert mentioned that the retreat wasn't chaotic. What kind of boats did people take? Did people have to ask to go to Taiwan, or were soldiers and other KMT folks taken along no matter what they wanted?
4. Are mainlanders who retreated to Taiwan considered refugees? I can see parallels on an individual level regarding fearing for their lives if they stayed in China, but an entire army and government system went over. Can it be considered some type of colonization? Both? Especially when over a million people fled to Taiwan.
5. My grandmother (who my grandfather married) was a poor Hokkien Taiwanese girl – were "mixed" marriages like this less common back then?

Thanks in advance!