is it ok to give a joint reception from both sides[girl and boy’s family] if nikah is done on henna function? can nikah be done on henna or mehndi function and joint reception given the next day? is valima still required or will this joint reception will do for valima?
All the events you mentioned are only cultural to the Indo-Pak continent. Nikah can be done on any function.
In Islam, all expenses of the marriage are the responsibility of the groom. Hence, Reception or Valima as is called is to be given by the Groom. Joint reception is fine.