Must burial be started soon after salatul al-Janazah or can it be delayed?

I have two questions which are basically derived from https://islam.stackexchange.com/q/51051/13438 . According to what I've seen in practice the funeral prayer (Salat al-Janazah) is held once the dead body was purified by ghusl and brought to the next mosque at a time of a daily prayer. It is usually performed after the fard prayer and then usually the congregation moves with the dead body to the graveyard. So does this mean that as per Islam a burial must be performed right or soon after the janazah prayer or are there differences of opinion? (If so please give some basic details like: opinion and who held the opinion) Secondly for relatives and friends who are far away there's the possibility of salat al-Ghaa'ib in cases as in that of the linked post it might be possible that some people performed the prayer before the actual salat al-Janazah or burial is this permissible?