Is it permissible to wipe over hair rolled with curlers during Wudu'? And is it permissible to wipe if all of the hair is rolled with curlers except for the front of the head?

Wiping the head is one of the agreed-upon obligatory acts of Wudu', and what is meant by it is directly wiping the head with water. If what wraps the hair prevents water from reaching the hair, it invalidates the purification, whether it covers the entire head or part of it. Ibn Qudamah said: "If he dyed his head with something that covers it or plastered it with mud, wiping over the dye and the mud is not sufficient." Wiping over the 'wiqayah' (the cloth with which a woman ties her hair to protect it from dust) is also not sufficient.