I hear that if you was the nappies in hot hot water it keeps them from having residue build up (or to boil water in a pot on the stove and pour it in the wash mashine and let them soak)...
Wont this make the nappies shrink????

You dont need to wash them in hot hot water.
30-40 degrees (centigrade) is hot enough with a decent washing powder.

I wash mine at 60 and they're fine

So Should I do a hot/cold wash then a cold wash after that? How should I dry them? theres no sun to do hang dry. Is Air fluff safe? Or low heat?

I prewash mine on cold, wash them on 60 with an extra rinse and either line dry them or hang them up inside on a clothes drier. Sometimes I finish them off on a cool tumble in my mums tumble drier but this can reduce the life of your nappies so I try not to do it too often.

i wash mine at either 30 or 40 and ive never had a problem

I wash mine at 40 and tumble dry them and they're fine. I wouldn't recommend tumble drying the liners though or plastic bibs for that matter.