Need help with pre-Qing Chinese Cash Coins

Hey guys, I recently bought a large lot of Chinese cast coins, most I could ID with the help of David Hartills book, but these four I can’t identify. Would appreciate some help, thanks!

1.

2.

3. This one is larger, probably 2 cash

4. I think this is a Korean 1 Mun, but I cant find this variety anywhere with the year on right side.

1. & 2. Vietnam Empire
3. & 4. Korea

1. Vietnam - Thái Đức Thông Bảo

N#64844

2. Vietnam - Gia Long Thông Bảo

N#38886

3. Korea - Sang Pyong Tong Bo, 2 mun (KM# 325). Minted by the Special Army Unit ("Yong" mint mark) in around 1742-1752, with serial mark “Suk” at the bottom.

4.  Korea - Sang Pyong Tong Bo, 1 mun (KM# 468). Minted by the Military Training Command ("Hun" mint mark) in around 1857. Serial number “1” on the right and serial mark “Saeng” at the bottom.