No? escargot for you? Mister loach

Loaches loooove snails, so I'm willing to bet your zebras will make a quick meal of a mystery snail. They will take bites out of its foot until it's dead. Not a pleasant way to go. I don't think there is such a thing as a loach-safe snail. Maybe nerites, because their shell extends beyond their flesh, but they are hard to find.

Mystery and apple snails will also eat plants, if they aren't being supplemented with enough food. Common pond snails and ramshorn snails will not eat live plants, but they would be an even easier snack for your loaches.

It's very possible that your amano shrimp fell prey to the loaches. Although shrimp can be very good at hiding. I almost never see all my shrimp. Maybe they're scared of being eaten, so are keeping a low profile. Also, they may be adjusting to their new surroundings, so may not feel safe coming out yet.

Loaches are almost as good as puffers when it comes to killing snails. I think you need to decide if you'd rather have loaches OR snails.

If you want good algae control critters for a planted community tank, go with a true Siamese Algae Eater (SAE) and/or a Farlowella (twig) catfish. I adore my Farlowella, she's the best algae-eater I've ever had. I have to feed zucchini because there's hardly any algae left. The SAE is also great because it will eat some of the tougher types of algae (and also eats almost any fish food, so there's no worry of starvation). I had 2 SAE's, but one chased the other non-stop and it really upset the tranquility of the tank, so I gave one away. Otocinclus cats are great, too, but I've had trouble with ones I've purchased around here (Chicago).

you can always try with ghost shrimp first. they're cheap, so you won't be at too much of a loss. I tried with a half dozen ghosties with my dojo loaches, and it went off without a hitch. From there I did a bamboo shrimp (love 'em), and might branch into Amanos and Red Cherries as well.

Most botias love to eat shrimp.