A few general questions below:
1) For all the Nawafil prayers, can we read silently or does it have to be aloud (e.g for Fajr nafila).
2) What is the significance of raising the hands at every Allahuakbar in Salaah? Is it recommended?
3) Can i merge by qadha Salaah with my nafila? How does this work?

1- recite silently
2- it's mustahab
3-no. not possible.