i've got a vegan toddler ds and a bf 4.5 month old dd so i'm very happy to swap ideas.
yy re ricemilk and arsenic.
we use soya milk and oat milk altho ds has just had some v loose nappies since we upped the oat milk which might be that change or just a virus. Have gone back to the soya milk for now but will try to increase the oat milk more gradually again.
we did baby led weaning with ds (so finger food not purees) presumably that what climber is doing too.
ds ate his own body weight in humous and breadsticks over the first year after weaning! he's gone off it a bit at the mo tho.
other things we found useful (either high calories, fat or protein): olives (not too many tho due to the salt), bananas, almond butter then peanut butter, dried fruit esp dates and raisins, the humble baked bean, home-cooked cake, coconut milk/creamed coconut, quinoa and lentils. Avocados would be great but he doesn't much like them!
He loves things like pasta, pizza, rice and potatoes for carbs/calories.
Nutritional yeast is brill for making 'cheese' sauces - he loves this on cauli or macaroni.
He also adores provamel soya desserts and yoghurts which are a great quick pud. I try to reduce his soya intake elsewhere (eg soya-free margerine, using oat milk for cooking, soya-free 'cheese') so he can have these without too much soya overload. When he was younger he had the soya 'natural' yoghurt with mashed banana.
he also has 1/2 tsp of flax seed oil a day plus vitamin powder (probably doesn't need it but i'm a worrier!)