Rice hulls (husks? I'm not sure) are supposed to provide N, and aerate soil. I've never used them straight, but they are mixed in with this composted llamashit I picked up. I've heard good things from good growers re: rice hulls.
(bagged) Mushroom compost is second only to (bagged) worm castings as a source of organic material, IMO. It is a little acidic, so if you add a large volume to your soil, add a little ag or dolomite lime in to balance the Ph. 1/2 cup of lime/cuft of total soil mix is a good starting place (2-3 teaspoons/gallon of soil). If you will be recycling soil, add a little more the first time you mix.
I should be a maxicrop salesman

I love the stuff. Be careful with strong doses during mid-late flower, as plants may want to start throwing whole new (un-ripe) flowers on top of ripening ones.
Kick ass easy soil mix for light feeders?
1/3cu ft peat or coco
1/3 mushroom compost or castings
1/3 perlite or chunky coco
1/2 cup dolomite lime
1/2 cup P guano or bone meal
Mix thoroughly, water in with 1/2 strength maxicrop. Water with 1/2 strength maxicrop every water from seed till the buds start to ripen. Water only or add molasses if you like till harvest.
EDIT - DUHHHH I'm a stone-job

I didn't see your recipe. I would back the nutes down to 1tbsp/gallon in your soil mix if you intend to also use the Pure Blend Pro/LK nutes. I would also advise that you use 15ml/gal pbp if you are also using liquid karma and amending your soil with dry organics. Remember, more is not always better

Letting the plants get properly wet and go properly dry is way more important than worrying about deficiencies with organic soil