Okay i need help these questions are driving me nuts! ( spoilers most likely)

These are the concepts that make clannad interesting
no one can explain them..
In #1 it is unexplainable ... but i can say that It is based in Japanese mythology belief called ikiryo is a manifestation of the soul of a living person separate from their own body

#2 is explainable

Tomoya was sent back in the past using his lightorbs to wish because he kinda regretted meeting nagisa because if he met nagisa he thought that she will die again but he still talks to nagisa and makes them a couple again and it fast vers l'avant, vers l’avant into the future timeline where nagisa is pregnant again. And while Nagisa is giving birth he remembered what happened in the other world..

im not quite sure yet but
i hope i helped a little ^^

I don't really understand what Fuko is.I just go par what they a dit in the show,that the real Fuko was sending her thoughts to them.

For Nagisa,do toi remeber the lights that appeared basically at the end of every arc when Tomoya helped someone?They explained as the montrer progressed that they are people's happiness that toi can accmulate to grant a wish.Basically the plus people toi help,the better a wishe toi can get.

Tomoya and Nagisa end up helping so many people and giving them true happiness that they aquired enough lights for a wish.After givingbirth to Ushio,Nagisa died.Tomoya had the opportunity to use his wish,but he wished for the wrong thing.The lights can only grant what toi REALLY desire,or it wont happen.And Tomoya,instead of wishing her to not have died,wished he never met her,but that wasn't his true desire.

After a few years,he reconciles with his
daughter,Ushio.But,she becomes ill and dies soon after they reunite.After this happens,Tomoya realizes that his true desire is to have Nagisa and Ushio back.Then all of the lights he got granted him his wish,bringing him back to the jour Ushio is born.But,instead of Nagisa dying after gving birth,she is still alive.

I hope this helps.I know my explantion for Nagisa was better,but I just don't about Fuko.All I know is that she comes back and is real.Yay!