Just out of curiosity, why are you trying to use parts out of a $45 toy boat to retrofit a $25 toy boat? Toy grade parts don't have the capabilities of hobby grade stuff. With hobby grade parts, you can install a brushless motor with a matched ESC, be able to use better battery packs and have a radio system that will have longer range and, if something goes wrong, it's repairable or replaceable. I just went and looked up your two toy boats and and wondering why you're spending the time on them. You're $45 UDI001 is only good for 15mph according the the Walmart website, making it not really worth the time.
To answer your question about using one boat's receiver with the other boat's ESC, the answer is probably going to be NO. If it comes in a big block, that usually means the receiver and ESC are built up as a mixed unit on a single circuit board.
If you want to upgrade your Nautique, you really need to think about spending some money on quality parts rather than trying to mash together parts from two boats that are really only good to run in a swimming pool