Well I never said it would mess with ALL scratch recipes and I also didn't say it would always not be able to handle it.
I never speak in absolutes like that... especially when I don't have a ton of experience.
As for the recipe advice... sorry... not going to screw with a perfectly fine recipe with a pudding packet. It totally moots the point of scratch baking for me. I also have the same aversion to shortening, but that's just me. I'm sure it works fine.. I just don't like using it (shortening that is). You can add coffee creamer to the list of things I won't use too. I have plenty of moist recipes that don't require the addition of pudding mix. I can see though how it could be okay since pudding packets have a lot of emulsifiers in them. I see no need to go there though... If you are going to go the route of adding a pudding packet you might as well just doctor a mix. Of course that's just my silly opinion.