The grains are being used based on what Pfriem is doing with their Pilsner. So, what could I do in regards to an extract? Should i use a LME or DME and based on Pfriem’s Pilsner here, what would you recommend?
https://www.pfriembeer.com/beer/pilsner
If you are extract based, then for this just use Pilsner DME. The Breiss one, for example, is made from 99% Pilsner and 1% Carapils, so you've got your pilsner malt and your head retention builder in it already.
The beverage cooler looks great, but I recommend getting a temperature controller with it. That way you can control temps much easier, and you can set to mid 30s for cold crashing up through 60s into 70s for ales, too! If you're going to spend the $$$, give yourself some flexibility.
I got this bad boy and wired it up to a plug for heat (heat wrap plug) and a plug for cooling (fridge plug). Attach the probe with some bungee to the side of your fermenter under some bubble wrap to insulate it. Set the temp and let it go. It sounds like you probably don't need the heat, though
https://www.amazon.com/gp/product/B00OXPE8U6/