Personally I love getting messy with applesauce. I love the consistency, smell, and taste. My wife just recently mentioned some foods she didn't like the taste or smell of and applesauce was one. I'm searching for a good substitute for applesauce. Same consistency and feel would be nice. Also something not nasty savory. I'm open to any kind of brainstorming.

I could suggest oatmeal. It's got similar bits to applesauce in it. But it's smoother (actually slippery). You could flavor it any way you want, because it is kind of neutral. Maple syrup is fun with it.

Do you have to cook the oatmeal first or can you just mix it with warm water?

A chemical change takes place when you cook the oats past a certain level. For us, making two large containers of oats at a time, it only takes 5 minutes when start with the hottest water we can get from the faucet. Remember that oats thicken as they cool, so make them really runny. And let them cool enough that you can jam your hand deep into the pot or bucket without getting scalded.
Test your mix proportions on a small batch before you commit to making enough oats to fill a pool. Normally, the mix ratio is 2 parts water to 1 part oats. 3 to 1 is better for pouring. You can thin your oats as they cool, if you made them too thick.
Insider trick: I use the paint mixer on my screw gun to make sure I produce as smooth a goo as possible. Otherwise, the result is more akin to lumpy cereal.

I always wonder if there is a difference in UK/US 'applesauce.' I've heard it mentioned on the and stuff as almost like a baby food or dessert,something appley-sloppy, fairly bland... therefore ideal for gunging!
I might be wrong but as i understand it applesauce here in the UK us a sour-sharp condiment, sold in small jars...would be a bit stingy for sploshing. We mainly eat it with pork. My hometown of Sheffield is sort of famous for it's 'pork sandwiches with everything' - stuffing,crackling,applesauce,mustard...in fact once Covid-19 is over I'll be going munching one of those bad boys from my favorite cafe

Yes Lad, American apple sauce is runny, clumpy with apple mash, usually sweet, and not often considered a spread. For spreading we use apple butter, apple jam, and apple jelly.
On this side of the pond, apple sauce is even packaged in cups to have as a side in a box lunch. While it can accompany meat like pork on a plate, it is usually on the side, rather than on top.