Hate to be the bearer of bad news but no pleco species should be housed long-term in a 10 gallon tank. Even the smaller bristlenose grow to around 5-6 inches. Plus they are extremely heavy waste producers from day one.
If you added all these fish (and frog) at once to a tank that housed only a betta with a relatively low bioload, it is going to take a week, maybe more before your beneficial bacteria is able to process the additional waste. This is why I asked what your water parameters were beyond 'fine'. Stress caused by even trace amounts of ammonia can cause outbreaks of disease such as velvet, columnaris and ich.
So while it's fine if you cure the ich, be aware that your tank is still going to be overstocked and unless you have a filter with adequate biological filtration you are going to run into problems with your water quality.
Also I am not a big fan of using salt and high temperatures for anything but very mild cases of ich. I prefer just to use a medication, follow the dosage recommendations to the letter and know for certain I have killed it. If the ich is bad enough to be killing your fish (been there, done that) you are going to need to medicate. I saw results 48 hours into my treatment and didn't lose another fish after I started medicating.