The excellent answer to the question Why can applesauce be used in place of oil? points out that one of the key reasons for using applesauce in quick bread type recipes such as pancakes is the pectin. Pumpkin also contains pectin. Therefore pumpkin should provide a similar effect on your recipe as the applesauce.
What the pumpkin puree won't provide is the sugar that applesauce provides. You will likely want to up the sugar provided by your recipe to account for this, unless you routinely use unsweetened applesauce. The water content between pumpkin puree and applesauce will also be different, as will the exact proteins.
I would suggest starting with a one to one replacement of pumpkin for applesauce for a very pumpkin-y taste, but you will have to experiment. You will also want to add sugar to taste. If you want a more subtle flavor, consider substituting only part of the applesauce with pumpkin.
It is no wonder you can't keep them whole. There isn't anything in the recipe to give them integrity.
A normal pancake has lots of egg and lots of flour. When you are frying them, the proteins of the egg uncurl and connect to their neighbours to set in a loose, weak mesh. You know how the egg white sets when you fry an egg without whisking it? That happens in a pancake batter too, but much weaker, because there is a load of other stuff swimming around, so the protein molecules have less neighbours to build their connections to.
Then there is the flour. As usual, when you heat a batter, the gluten proteins in flour do the same thing as the egg white proteins, building their own mesh which permeates the whole pancake. While there is less gluten building than in a well-kneaded dough, it is enough to make the pancake hold together.
In your recipe, this just doesn't happen. You have no gluten content at all. So the stronger holding-together-part falls away. Unlike wheat flour, almond flour has no gluten. So it isn't contributing to holding the pancake together.
So what about the whole other protein you have in there? Well, the point is, it is already set. Ricotta, whey protein are both cooked proteins. They can't uncurl and connect a second time. So instead of helping the binding, they are inhibiting it. Every egg protein molecule which could have connected to a neighbouring egg protein molecule in a more fluid batter now keeps bumping into almond, ricotta and whey particles, to which it can't bind at all. So what you have here is a mixture of wetted powders without a binding agent. No wonder it can't hold together.
The best way I can see here is adding wheat flour back. You don't have to sacrifice all of your almond flour. Make a partial substitution, and also substitute part of the whey protein. This will keep the proper viscosity of the batter, while preserving the almond flour taste.
The way the recipe is constructed, however, it looks like somebody decided to exterminate all the carbs in it just because. If you are determined to keep your pancakes zero carbs, you can try throwing out all the whey powder and adding egg white instead. I can't guarantee this will be enough to do the binding, but if you insist on "real pancakes", this is worth a try.
I don't think there are any other traditional techniques you can use to improve your "batter" bonding. Of course, nowadays you can experiment with additives. Transglutaminase looks like your best bet. You'll probably need lots of tries until you get the recipe right, but it should bind the cooked ricotta proteins well enough. You don't want a superstrong binding for this application.
Best Answer
Oats can be a good substitute, just blend them and use as normal flower.
250-300g oats, two medium sized eggs, 300 ml milk and 1/2 portion bag of baking soda.
Normally I use a mix of flour and oats, so I have never tried it with oats alone but I guess if you do not have flour you can try.