OK, you mention the following:
Fussy eating
Tonsils
Mouth breathing
Silent reflux
Glue ear
Milk monster
Night waking
Coughing
DS1 was remarkably similar, not so much at 2yo but more like 3-4yo.
When he was around 5yo, I read on here that there was a link with reflux and tongue tie. I dug and dug online to find information about this, there wasn't much but I found a tongue tie support facebook group where there were many others suffering similar. Eventually, I pieced the whole thing together and found that pretty much every problem he had was related to the tongue tie.
Fussy eating - he could not chew and move the food around his mouth properly because of the restricted movement. He rejected anything that needed more than a few chews such as meat and textures like sweet potato which can sometimes be stringy, meaning that if he swallowed some of it without chewing properly, a whole lot of it also got pulled down by the stringy bits.
Large tonsils - they actually turned out to be normal, but they looked huge because the back of his tongue was tied tightly which meant I could see the whole of his tonsils without a tongue depressor.
Mouth breathing - he also has a high, narrow palate, which is the result of the incorrect swallowing action of the tongue. The tongue smooths the palate in utero and beyond and ties can affect the shape of the palate. The high palate encroached on the space for his nostrils which caused mouth breathing.
Silent reflux - he verbalised a burning in his chest and being sick in his mouth when he was 5yo, but I suspect he was suffering from this for much longer. He was swallowing down a lot of air when he was eating and drinking and this would come up and bring the stomach contents with it. He had an endoscopy, but all it showed was irritation from the reflux. I guess it's not technically reflux which is usually caused by a weakness in the sphincter at the top of the stomach, but almost identical symptoms, none of which were relieved by the usual self help measures. He was also very bloated and windy as a result of the air he was swallowing.
Glue ear - for around 2 years, he had congestion, noise and hearing loss. This disappeared shortly after his reflux stopped which makes me wonder if there was stomach fluid being forced into his eustacian tubes. Again, the high palate restricts the space available for the tubes meaning that they don't drain properly.
Milk monster - he wanted to feed like a newborn a lot of the time. I think the milk soothed the pain from the acid. I hadn't planned to nurse him for nearly so long, but it was clear to me that he really needed it. Not as in nutritionally, but as comfort and relief from the pain.
Night waking - he was a nightmare. He woke several times a night until he started at school aged almost 5yo. He did have some bouts of apnoea too, related to the high palate.
Coughing - he had a persitant cough for months on end. The docs kept banging on about an inhaler, but I knew it was not an asthmatic cough. The cough stopped as soon as the reflux disappeared.
Sorry for the essay! There were more things going on with him too - allergies/intolerances, orthodontic problems, underdevelopment of his mid face (not that you would notice unless you knew what you were looking for), curve in his neck, possibly from the tensions caused by the ties which had a knock on effect on his hips, knees and ankles.
He had his tongue revised and the reflux stopped overnight. It turned out that it was not revised completely, but it was enough to stop the gastric problems. A few months later, we saw a dentist who specialises in ties and he revised it properly and referred us to a local dentist. He is now 1.5years into early orthodontic treatment (he's 8yo) which has started to widen his palate and draw out the mid face. Every single one of the problems I have listed have disappeared.
Could your dd be suffering similar? Ties are not always obvious unless you know what you are looking for. DS1 had a whopping lip tie too.
Other problems associated with ties that I haven't mentioned are breastfeeding problems (ds1 was very inefficient but thankfully I was never sore), speech problems, dribbling, dental problems - sometimes the tongue cannot reach all the teeth so can't "sweep" them clean. Also, some upper lip ties can form pockets which retain milk and food. This can cause decay on the front teeth from the prolonged contact with the surface of the teeth.
Jeez, sorry this is such an essay! There is virtually no knowledge of all this in mainstream healthcare. I hope that sharing our experience can help people who are in the same boat. I was incredibly frustrated that we saw one doc for the gastric stuff, another for the ENT stuff, dietician for the fussy eating, another for allergies etc. There was no joined up thinking!!