Hi Reed,
If you are using a mold, then yes, the Resin Obsession super clear resin is a great choice. You can find it in several sizes here: https://shop.resinobsession.com/collections/resin/resin-obsession-super-clear-resin If you are using a bezel or something else, then I am happy to make a different recommendation.
As for using flowers in resin, we have several articles on that here: https://resinobsession.com/tag/drying-flowers I don’t have an article on using a bug in resin, but the same concepts apply. Make sure your bug is fully dry. I even like to dip them in resin and let them cure on a piece of wax paper before including them in the resin. This will seal bubbles in or out, otherwise, they may show up in your casting later.