In earlier years I did much the same thing with a Thirsty Mate, and never had a problem. I still carry a Thirsty Mate.

However, my experience is that when the boat is really in trouble, or you come to the boat while it is at the dock but up to its gunwales, the last thing in the world you have tme to do, or want to do, or can do is to arrange the bilge pump exit hosing. I believe that standard safety practice is that the bilge pump be operable from the cockpit - totally.

Unless there is some way to secure or to hold the drain hose in the sink, my experience is that hoses flop around and will eventually make a mess in the cabin, pumping water back into the bilge.

The sink drain hose is not large enough for a decent sized bilge pump. Even using a Thirsty Mate to pump out the bilge, I fill the sink and have to stop while it drains. A bilge pump requires 1" to 1 1/2 inch hosing more or less straight through

You might want to consider, putting the hose into the cockpit, rather than the sink, because the cockpit drain hose is larger capacity and there is a bigger plenum.

Just some thoughts.