Corgi, I think cashews are legumes not nuts (like peanuts) that may be why you can tolerate them.
I'm still in testing phase of my intolerable foods... I don't do very good at it unless I really commit. Otherwise I just eat whatever. Oops.
However, I too have OAS so I avoid raw nuts, esp almonds and hazelnuts, and dates, apples and cherries. If those items are cooked though they are fine. Macadamias actually seem to be OK raw. I'm actually not a big nut fan anyway.
I am starting to think that coffee bothers me... just avoided it for a week and am having a cup right now. Let's see how that goes.
Grains and soy definitely make me feel sick. Corn not too bad though.
Sugar and carbs and maybe fiber. I am really sensitive to them it seems. I have to have ample fat and protein with every meal and feel jittery if I don't. Unless it's right after a workout, I keep them minimal. If I do "gorge" on them, my skin gets noticeably oilier and like I said, I feel jittery. Even eating a big salad, if there's not a big slab of meat with fat, my stomach will feel lousy too.
Dairy is probably not good for me, but I refuse to accept it I love cream and butter and cheese darnit. Milk I can live without... but not cream and butter! Nooo. I have to do a serious elimination of ALL dairy, then add stuff back in one at a time.
As for substitutions, if it were a case like I wanted coffee with some cream, I'd just use nothing or maybe some coconut milk. I don't really sub anything, I just avoid it and eat more of what I do like.
How funny, I was just looking up sources of 'good fat' so that I'll have more options than nuts and avocados to eat with supplements/fruit. Looks like my other options, according to these sites, are things like 'vegetable spread' or 'canola oil'. Coconut and animal fats, of course, are bad.
I actually have a pot of soup with lamb/chicken broth, some veggies, and goat butter so I'm golden on fats atm. I usually just don't have meat on hand until dinnertime. Cashews are legumes, eh? They're probably not very good for me then (I don't soak mine either, probably should start doing that...) but I like something crunchy and bland yet with some flavor every so often and I'm not about to pick up some crackers or bread for toast. My veggie pulp pizza crust with soaked flax meal has been treating me well but unless i'm making a pizza it's not good for snacking on its own.