Welcome to APC! 
The snails that you saw burrowing into the substrate is most likely Malaysian Trumpet snails. As for the little football shaped one, you are right, it is a pond snail but I have never heard of them eating live plants before. I have a ton of them in both my 10g and 2.5g and they have never eaten any of the live plants. Only dying leaves, fish wastes, uneaten food and algae.
I don't know what to say about the Ramshorn snail though. If they are very tiny and it looks like their shells shift to the side when they are walking about then I'd say don't worry about it but there is a ramshorn snail(Marisa cornuarietis) that will eat all plants regardless of whether they are alive or dead. If you go onto the applesnail.net site, click on the Species link then click on the Marisa link underneath the map. Look for the name of the snail I mentioned and you'll find out more about them.
The snails that you saw burrowing into the substrate is most likely Malaysian Trumpet snails. As for the little football shaped one, you are right, it is a pond snail but I have never heard of them eating live plants before. I have a ton of them in both my 10g and 2.5g and they have never eaten any of the live plants. Only dying leaves, fish wastes, uneaten food and algae.
I don't know what to say about the Ramshorn snail though. If they are very tiny and it looks like their shells shift to the side when they are walking about then I'd say don't worry about it but there is a ramshorn snail(Marisa cornuarietis) that will eat all plants regardless of whether they are alive or dead. If you go onto the applesnail.net site, click on the Species link then click on the Marisa link underneath the map. Look for the name of the snail I mentioned and you'll find out more about them.