Yay Liz for sals and amines tolerances!!! I guess if your trial avocado - very high salicyalte and no problem then you know shes ok. I would give the avocdao just a tad fmore than 3 days though to make sure.
I gave chicken at about 6.5 months. I was very keen to start meat so he could get enough protein and help him with his night sleep & dairy free. I give protein with two meals a day since 7 months one meat and one beans. The dietician coudn't stress that enough. By 7 months , he was on lamb and beef too which means that he can suck on frenched lamb cutlet bones and things like that - he loves it loves it!
Rice cakes are extremely easy for them to eat, they suck them. He had those just on 6 months. Other foods just make big enough so he can grab with his fist so quite big peices and he sucks and crushes them. At first alot goes to waste then they figure out how to eat them after a few weeks.
Kai is one week off 8 months now, he is on 20 foods, all introduced with the 2-3 day rule.

He has ALOT of intolerances.
As for grains, I started gluten free grains just before 7 months, they are no problem at all. Just as long as they don't contain wheat

Since I am gluten free we have a lovely gluten free toast that has no preservatuves or dairy do its really nice to give him toast with dairy free butter too

So that includes millet and amaranth too.
I usually use water and about 10ml of neocate for porridges. With the quinoa, I mix a little rice cereal & amaranth in too for bulk, Its should be about 2 parts liquid one part water when you start. Now i mash a bit of bannna in. (as we are not on pears yet).
Now he is at the point where he can eat *nearly* anything in my diet , I have been giving him fried vege and meat patties flavoured with leek & shallot (instead of onion due to the salicylates) - things like that.
We have a very strict vege introduction list too. He still hasn't tried and moderate salicylate yet

Oh, risotto made with stock& veg is another good one.