Yes, 10 years is a long time to go without repotting.It's depleted of nutrients and most likely soil that keep the roots healthy. Since the Schefflera and Snake have different light requirements, I would pot up each different plant
in their own pot, so you will be able to downsize to smaller pots
The Scheff can take high light/direct sun, the Snake, med indirect to low light. Give both plants
about an inch between the rootball and inside wall of of the pots, keep them slightly snug and use a soil that is well draining.