I can't see the pictures you posted... so I can't confirm if it is ich or not. Ich is very pronounced white spots, they are small, and should be fairly uniform in size. If they are all different sizes, and fuzzy, that may be fungus. Ich does not cause 'cloudyness'.
Now on to ich...
Ich is a parasite, and has a life cycle. While on the fish, it is immune to medication and can not be harmed. Once it is done feeding, it will drop off and fall to the bottom. At this point it will multiply by the hundreds/thousands and again is immune to medication (and salt). Once it is done reproducing, they'll become free swimming and look for a host. They do not live long in this stage, and they are vulnerable to medication at this point.
The time it takes for this cycle to proceed is entirely dependent on temperature, the higher the temp the faster it will proceed. Recommended is 86 degrees. It has been shown that at 86 degrees ich is no longer able to reproduce. With some fish, it is possible to go all the way up to 91 degrees, which is the temperature that will outright kill the ich. A betta will be more than fine at 86 degrees for a week.
I would strongly recommend going up to 86 degrees. The constant water changes will be very stressful though, I'd really only do that if your ammonia is spiking, which is possible in a small bowl. Stress weakens the immune system, a normal healthy fish is more than capable of warding off ich on its won so whatever you can do to reduce stress is good. Maybe do partial changes daily, instead of 100% so you're not cupping him daily. A liquid ammonia test would be good to ensure you're not building up ammonia (which causes more stress than water changes).
Normal treatment in an aquarium that can hold a cycle (beneficial bacteria cycle) is to raise temp to 86 and add salt OR medication, not both. Salt is the 'natural' method, but medications work faster. You then just leave everything alone for 1 week. With live plants, you can not use salt.
Personally I've had good success with Coppersafe. Our Betta had ich from the store, the first day was ~30 spots, after 24 hours they were down to 3-5 spots, and by the second day of treatment all the spots were gone, and no new ones returned. We left the temp up and did no water changes for 1 full week. We had live plants, so there were no issues with ammonia/nitrite.
For your decorations, they will be infected with ich. Generally the entire tank must be treated. Ich can not survive without a host though, so removing them will work too. Just be aware that as mentioned above, ich has a life cycle dependent on temperature. If the bucket you have these decorations in is not heated, the cycle will be slowed considerably (weeks).