Can I play the Beta in Single Player?

[DMS|Instinct]

will the single player skirmish mode in the released version of Assault Squad be more like the original MoW/Red Tide or should I NOT buy it because it will just be more of the kamikaze stuff i'm seeing now?

Not sure what you mean with kamikaze style, but the difficulty you set also sets the amount of troops. So on easy you should have a pretty fair and less demanding gameplay with a lot less units.
However, the skirmish is the core feature of Assault Squad and comes with 16 missions for 5 nations and are similar to the ones you see now. As this is a beta there will be changes for the release version for sure but not drastic ones.

After the release you will most likely have the chance to obtain more skirmishes via DLC that feature different sort of gameplays.