Kaali isn't different to other party members. She just can get hit and knocked out like everyone else. Maybe you are lucky or your stats for her are too high to have any problem with the enemies in the current area.
Well it's a new area and the difficulty is higher. You can't hope to be always well prepared if you stay on the same level and equipment.^^
The game in its current state is nice to play and offers stat boosts to veteran players if they don't want to start weak again.
Feel free to support the game on Patreon or Subscribestar, links are in the OP.
You can make her yours truly if you have sex with her but you can't marry her.
You can date Nancy on Mondays, when she is at home and not working. To propose to her max her relationship points and have a gold ring with you to be able to propose to her on a date.
Both Eve and Elizabeth are not open for marriage.
You can't, she is very comfy in her swamp.