Has your bun stopped eating altogether? If that’s the case you shouldn’t let more than 6-8 hours pass before you contact a vet. Not eating is extremely dangerous for a rabbit.
The discharge and wheezing means you need to see a vet anyway. Especially the wheezing must be treated asap because it can be the start of pneumonia. It sounds like it could be pasteurella but there are other bacteria as well that can cause these symptoms. Your vet will probably prescribe an antibiotic (baytril) and maybe a decongestant. You can then ask your vet about herbal treatments that might be used together with the prescription meds.

But the inappetence is top priority.

I agree with Bam. BTW I’v looked at herbal options myself and there are no known dosages. Only what individuals have tried, and posted on some blog. Unfortunately, the wheezing sounds bacterial, which requires antibiotics. It’s not the same as us humans taking ecchinacea for a cold (which I find works amazingly well!). This could be way more than a cold, for your bunny. If we got pneumonia, or bronchitis, we would take antibiotics, not Echinacea. The loss of appetite could turn into an emergency in 24 hours. It could be a sign of many things. Stasis, not feeling well because of whatever is causing the wheezing/discharge, gas pain, or a myriad of other causes. Rabbits can go into liver failure if they stop eating. Even just slowing down – could lead to stasis. Like Bam said, if you can get your bunnies to a vet, you’ll probably be given baytril for them, or SMZ. It is handy to have Sherwood Forest digestive tablets in your first aid kit, for the Vitamin B content. I find it handy when my little guy loses his appetite. But it doesn’t fix the original problem, it just helps to limit the symptoms.

Get your babies to the vet, it’s the best thing you can do for them right now

Vanessa is right. Rabbits do not get colds. URIs are caused by bacteria, which herbal treatments are not really going to help with. Nasal congestion isn’t as bad as chest congestion. But, if left untreated, the bacteria can spread to the lungs causing chest congestion. This is definitely concerning because the next step would be pneumonia.So antibiotics would be the way to go here. Most vets will just start with a broad spectrum antibiotic like Baytril. If that doesn’t clear it up, then they might do a culture to see what the bacteria is sensitive to.