Agar agar is a bit of a laxative, so I may suggest you find another thickening agent. I think the store you are looking for is a baking supply store for most weird flavorings and powders. Restaurant supply may also have aisles as well, though the good ones are harder to come by. If only the modernist pantry had a storefront.

https://modernistpantry.com/categories/ingredients.html

Liquid eggs are pretty easy too: Just pasteurize the darn things with a sous vide machine. Hold them at 130 for a few hours.

https://www.seriouseats.com/sous-vide-101-all-about-eggs

The internet has that at least?

https://shop.kingarthurbaking.com/items/dried-buttermilk-powder

For egg whites, it’s not too bad to make them yourself with a dehydrator.

https://www.littlehouseliving.com/dehydrated-eggs-make.html

It’s “buttermilk” just add water, so I suspect there’s some dairy flavoring of some kind in there.

EDIT: Yea, it’s flour, sugar, a leavener, starch, salt, a bit of soybean oil, some dehydrated egg whites, and dehydrated buttermilk

Yea, but the special edition with the HD textures is what is sold these days.

Or, you know, a cat or child climbed in and the door closed on them…