Water lilies can tick over fine in your drums, plonk 6" of fertile clay and soil in the tub. put a foot of water over the soil, weight the water lilies down with stones that don't smother the crown, the point where the leaves and roots are formed... Place the tubs where they don't catch for extreme midday heat
You can set aside water lilies like that for some time and they will thrive. The only thing that could spoil them is a severe frost freezing the water in the tub...
Regards, Andy
