Hello and welcome to the site and back to the hobby! Exciting times ahead I'm sure
With your equipment, I'm not experienced enough to comment, hopefully someone else post about that for you.
With your stock, the sharks raise a red flag to me with discus, I'm not sure they are compatible. You may need to check temperature compatibility with the Betta, Bristlenose and shrimps, as discus like warmer waters than most tropical fishes.
The plants sound good, I love live plants.
Depending on what size discus you buy will determine how many water changes a week you will need to do.
I hope some of this was helpful, and that other more experienced members will chime in soon to help