Unfortunately, there are trade-offs in how you approach the game's challenges and which ones your elect to complete first. The mausoleum is an essential pre-requisite for burial of deceased villagers. From the game guide:
ARTHUR’S TIP
Villager who pass on need to be carried by other villagers to the mausoleum, or they will be lost and forgotten forever! Once a skeleton is visible on the ground, the departed villager must be laid to rest within approximately 24 real-time hours in order to make sure that their memory is preserved in the mausoleum.