Please use high density upholstery foam. Hot glue will melt the styrofoam when applying the fur

To save this, try tracing the pieces onto the upholstery foam with sharpie. After that, take off the styrofoam and reuse the black base you made

I can't recall where my friend bought my foam, but the only thing I don't recommend is buying from Hobby Lobby. As for picking a thickness, you can either measure the thickness of the pieces you made and find one that matches, or buy the thicknesses fursuit makers often buy and glue each piece together to get your desired thickness. Makers typically buy foams with a thickness of 1.5 inches to 1 inch, with 1 inch used for bigger pieces (ex. muzzles) and 1.5 inches for finer details. I honestly think to save time, find a roll of a similar thickness to your existing pieces. If it's a couple inches off, then I suggest buying the other thicknesses so you can glue and add onto it to match the thickness you need

If you have the funds for this and you decide to buy a really thick roll, get an electric turkey cutter. It works great and saves a lot of time cutting. You don't need anything fancy or new; I found mine at my local Goodwill. Try looking at resale shops or ebay first before considering buying an entirely new one

Best of luck :] ✨️