I like the 1st and 2nd suggestion, they could be very useful.
Although in the case of the pop ups being annoying maybe there is a more simple solution. For example not allowing to receive friend requests when you are in bed/shower or playing a minigame. There are other situations when they can be annoying but i bet those are the most important ones and probably they are easy to fix.
Another option could be having a check box like we have for the DnD but that only blocked the invitations.
Although in the case of the pop ups being annoying maybe there is a more simple solution. For example not allowing to receive friend requests when you are in bed/shower or playing a minigame. There are other situations when they can be annoying but i bet those are the most important ones and probably they are easy to fix.
Another option could be having a check box like we have for the DnD but that only blocked the invitations.