is it possible to use two different themes? like could i use the rentry one for my main page but then also use the laundry theme on a different page with a link? or do things have to all be the same theme?

oh you can very easily use both. on your index.html (your homepage) you import the rentry-ish theme, then you make a new page and call it whatever you want . html, and you import the code from the laundry theme onto that. then you just have to link them together and they’ll work as separate pages on the same site.