"Your danger here is [...] the spores." Wrong. Some botulism spores do not pose a health risk to people with a normal immune system. They are everywhere and you eat them all the time; that's why it's so easy for foods to get into contact with them, grow the spores, and produce the toxin.

You wouldn't want to use liquid to make molds of the ones on plates/backings, it'd clog the little holes

The plates are definitely not for starch impressioning: why would there be holes around the shapes? Maybe the loose masters are; would need to see the back. Could use them for either casting, vacform, or impressioning. It's kinda strange to have just one of each for casting/vacforming, but if you have a collection that are similar where they'd form a sort of set with similar size and detail (e.g. the 'eggs', the more detailed 'flowers', and the 'toys/stuffed animals'), producing them together might make sense.

@Joe the positive masters (plugs) don't usually need vents unless it has a bunch of two-way concave depressions and the surface is very smooth. When the softened plastic drapes over the master, if there are any crevasses (like the cracks in the turtle shell, or even just a gentle), they're usually enough to let the air get pulled out. If there is a problem with the master after doing some runs, you can always drill a vent later. Unlike your composite bagging, the plastic isn't a liquid, so it won't perfectly seal unless your surface finish is extremely smooth.

As far as I'm aware, air in sausage is always a fault, even in 'great quality sausage'. In smoked sausage it's not too bad, but can lead to a 'crumbly' product. In fresh sausage, it's annoying because when cooking, 'windows' of air can dry out and crack more easily. In dry-cured sausage, it's especially bad because when aging the oxygen can turn the fat rancid and bad mold/bacteria can grow in the void. Commercial stuffers include vacuum pumps to remove trapped air in order to improve quality and consistency.

Not an issue that it's an anecdote, but that n = 1. Try it a dozen or so more times on yourself or feed it to a few dozen other people and we can get some good stats.

Why add both some amount of acid and base?

Using the shredded chicken in something with a very flavorful sauce (I'm thinking enchiladas) where its flavor would be very background would be the best bet I think.