Hey @JoeyKarczewski!
I know this is an older post, but a friend and co-worker of mine @TRF and myself did figure out a way to create responsive masonry layouts utilizing Retool's Custom Component using the Bootstrap library, HTML & CSS 
You can view his post here, and if you haven't found a solution for implementing a masonry layout we would be happy to show you how we utilized this solution!
Hope this at least helps with that portion of your suggestions!