There are some products you can wear that repel mosquitoes — have seen them in pharmacies and hardware store (but have no 1st hand experience).
^^^^ Re #19 - Can you carry aboard? Yes, as long as it is in 3 oz bottle or smaller, there should not be a problem (as I noted in #12). I have carried it onto multiple different airlines leaving through multiple different airports headed to different countries in Asia, US and Europe - Thailand included.
There is also a 1 oz DEET repellent stick called Repel Sportsman. I’ve also carried that on - no checks at all as it is solid (like a small deodorant stick). It is also very effective, I’ve used it hiking in multiple equatorial jungle, buggy locations. I personally prefer picaridin, but this stick is handy to carry in a day pack or pocket.
My daughter took some DEET-containing product on her trips to Vietnam and she treated her clothing with permethrin ahead of time.
DEET wet wipes are also a thing. I used to carry a few in a ziplock bag when we took trips.
Along the lines of the lemon treatment, I used to use lime juice for hiking. I bought one of those plastic limes filled with juice and rubbed it on exposed skin. It didn’t make me sticky or feel icky in any way. It was quite effective except in the most extreme situations. I carried a small DEET repellent as backup (rarely or maybe never used).
Now I have repellent clothing and a DEET spray as backup.
When I went to Africa I purchased DEET cream/lotion from amazon. Small TSA size tubes and less chance of leakage compared to liquid especially once opened, although not as convenient to apply. It was very highly rated. I think it was/is? used by the military.