The hubpost library was set up so that the thumbnails linked to pages (or posts). Then on those pages you could download the media. I was imagining it that way. You could also set up the tiles to look very simple with spacing between them if you increase the padding and set grids="plain". That would like almost identical to the hubspot library page. If you want to have two categories, you set up two separate grids and call for only the page/post ids you want included in that grid.
Now, I don't know much about custom search options but it sounds like with some digging that should be possible. Lastly, don't be intimidated by coding. It is well worth a few days to at least learning the basics at codecademy or other free online tutorials. Like you said, you will need to customize eventually.