Your snail might have a collapsed lung. Take it out of the tank for about 15 minutes, put back. If the bubble returns then its a collapsed lung and it will probably die soon. Sorry buddy. 😞
I'm no expert but it does look like Anubias. I had something similar happen to me. A piece of the Anubias rhizome broke off, landed in a crevice in my driftwood and started growing. They're slow growers so it was a while before I saw the leaves.
I use a 16 oz plastic cup with holes all around to slow the flow. You could also get a cheap pitcher and drill a few holes on it. Use the handle to hang it on the tank. Just an idea.
Hi! They wont be adults in 3 months but will be juveniles. At that point you can use a net to transfer them. This is not the best picture but these are my 3 month old WCMM. They still have the blue lines (makes them look like neon tetras) and they're about 3/4 of an inch. I think you will be fine when it's time to move them.
Make sure the main ingredient is cyanoacrylate. When in cures it becomes stable and does not react with anything else (including the water) making it safe for fish. I use it and I have no issues in my tank.
Have you tested your tap water? Or whatever water you're using for your changes? Sometimes if you have well water you could potentially have some nitrite in it.
I think YouTube videos should be used as a guideline. Different places have different water. What works for one night but work for others. There's no one fits all solution. And like @daggaz said, check your water for your own health too.
Maybe adding 2 gallons of water created a significant swing in water parameters. When I have to top off i make sure it's not more than 1/2 gallon at a time, but that's what works for me.