Baseless beliefs

Q: Regarding menstruation periods I would like to ask the following questions:

1.Are women allowed to have a bath whilst in haidh and nifaas? (I know that this will not make them pure from najasat but are they allowed to bathe because of hot weather and hygienic reasons?)

2. Are women allowed to do istinja using water whilst in period? (Women in our area refrain from using water saying this causes illnesses and is against the laws of haidh and nifaas; is this true?)

3. Are women allowed to drink cold water and ice-creams and other cold products during haidh and nifaas? (Again women in our area refrain strictly from this saying that it is not allowed both for medical and Islamic reasons?)

4. In our area women that are in haidh or nifaas still read salaah (in pretence-meaning that they don't recite anything but pretend that they are reading) in the presence of their fathers and other males using the excuse that they shouldn't know that their daughters, mothers or sisters are in this state. Is this allowed or not?

Self hypnosis

Q:

1. In islam can you listen to self hypnosis? Basically self hypnosis is deep relaxation then you do visualisation or make suggestions. I want to know is it haram or halal?

2. What about meditation, is it halal or haram?

Surma while fasting

Q: Does it invalidate or nullify the fast if you apply surma and sleep during the day? My father has been arguing that while fasting if you sleep during the day with the surma, it nullifies the fast as per some mufti he heard. kindly guide me.