As far as items rendering doesn't support techne models anymore something must be done with all items and itemblocks with "custom" models.

• Graves
• Memorials
• Spawners
• Candles
• Skull Candles
• Piles of bones
• Corpses

One of solutions is use a "plain" textures for graves, memorials, Spawners, Skull Candles and Corpses itemblocks instead of models(it will required to fully rewok how grave/memorila type store for its itemblocks - store it in metadata)

As for candles - rework its model to a new json system. Do not forget to remove its tileentity and some another unrequired classes.