Hi everyone! Newbie here!

I've already done a ton of research on Pacman frogs, I'm planning on getting one for Christmas, but I still have some questions I wanted to ask just to make sure I have everything figured out.

1) Is this a good substrate?: http://www.chewy.com/zoo-med-eco-ear...onut/dp/123767
2) Is this a good heater?: http://www.chewy.com/zilla-heat-mats...rium/dp/129072 He/she will be in a 20 gallon tank.
3) I know I have to condition the water in a shallow water dish. I own fish and have dechlorinator for them, will the Tetra Water Conditioner be okay?
4) Lastly, I plan on feeding crickets (maybe nightcrawlers occationally), but will the ones sold at pet work or do they need to be a specific species?

Sorry if these are super obvious questions, just want to make sure everything is perfect!

Thank you guys for your help!