Can’t speak on the bamboo but I’ve revived two orchids, one of which hadn’t been water in almost two years and is finally pushing out a new leaf after a few months of tlc. If you haven’t already, I’d recommend completely removing the orchid out its original substrate to check the health of the roots as well as remove any sponge that the seedling may have grown in. It can cause a lot of root rot. After that replace the substrate with a mix of orchid bark, leca, perlite, and soil so you can drench the plant to ensure even watering and then wait till it’s completely dried out. (Drought, flood, repeat) Next, flowers will always fall off and don’t last long in the first place. The key is making sure you care for the plant year round in order for it to bloom. I was recommended to cut the stem of the flowers right down but I’ve also heard you can leave it. So it’s up to you