Hi! I am a nursing mama and childbirth educator and breastfeeding counselor.
Good for you for nursing!
How old is your baby? My youngest is now 8 months old.
It sounds like you are giving your baby great starting foods.
Some other healthy ideas:
-quinoa and tofu have healthy protein
I mash up both and mix with fruits and veggies. They are both so mild that they blend with everything.
There are vegan DHA supplements made from algae that seem to have been shown to increase the DHA content in the body.
And yes, DHA in the mother's diet *does* affect the DHA in her breastmilk. So, as you said, the type of fat in your diet does change the type of fat in your milk, although not the quantity.
Remember, by eating lots of healthy plant foods and avoiding processed foods with unhealthy fats, you will be throwing your breastmilk into a healthy omega3:omega6 ratio.
It sounds like you are doing a great job!
ETA: Remember to take a good source of B12. If a mother's diet is lacking in B12, her milk will be too. You can also start giving B12 to your baby when solids are started, so now might be a good idea.