THE only things that are not safe is whole nuts, whole round fruit/veg like grapes and cherry tomatoes (and all stoned fruit needs stones removed) and hotdog sausages should be cut up as they are quite throat shaped when whole and very slippery. I have also read that popcorn is dangerous and tbh I find myself gagging on bits of popcorn stuck in my mouth from hours earlier, so I tend to agree with this. Sweets are also not safe but as I dont think of these as food I forget to put them on the list often! No salt and no raw honey either but thats not about choking.
The number of teeth a child has wont affect their ability to eat (although extreme fussiness and food refusal during teething is very common) - my daughter didnt get her first tooth till 11months and her second at 14months but she was eating full meals of family foods by 10months!
So if you are making food for yourself you can give it to LO as long as youve left out the salt and doesnt have hard round things in so:
Pasta with homemade sauce (cheese, bolognaise, tomato and basil etc.)
Vegetable stew
Roast chicken
Grilled fish
Cooked broccoli, carrots, parsnips, squash, potatoes
Toast - plain or with hummus or nut butters or scrambled eggs
Mashed potato
Porridge
The list goes on. Cooked veg and soft fruit is easier to start with as its a learning curve for them so hard fruit like apple can cause a lot more difficulty and gagging, ditto raw carrot/pepper.
Gagging happens, quite a lot at first but true choking is much less common.
If your worry from your son is preventing you from experimenting with new food for your daughter, paediatric first aid courses can ease your mind and inform you of the difference between gagging and choking and ensure you have the right skills to deal with a true emergency.