New to soil

I have a crop started in hydro and have that down somewhat. Plants look good etc. My buddy (a soil grower) was getting ready to throw away three vegging plants, a sour diesel, afgoo, and some kind of kush (name escapes me now). They're about a foot and a half and root bound. My brother bought two bags "Down to Earth Pro-Organic Mix" from the grow store and I'm curious if anyone knows anything about it. I researched growing hydro for a while before I started but these plants kind of came out of nowhere. The bag says 35% coast sphagnum peat moss, 35% coconut coir fiber, perlite, organic worm compost, and diatomite. Also has Mycorrhizal fungi, natural wetting agent (wtf is that? Water?), and Organic Fertilizers. I know how to transplant I'm just wondering:
A) Is this going to hold too much water?
B)Should I mix it with something else?
C)How long does fertilizer last in soil before it needs replenished? (Don't worry I already have nutes...)

it sounds like it might hold water. maybe just add more perlite? other than that it sounds fine.
it should say how long its gonna last on the bag. i like adding nutrients to the soil so i have more control over it. i always do a mini flush when i water so i can flush out the old and add fresh nutrients. works for me haha

the wetting agent just means itll be easier to water when its time.i mean usually when soil drys out its pretty difficult to water because the water tends to run off the surface of the soil and down the sides of the pot.also after watering there can sometimes be dry spots within the soil.to stop this from happening some ppl use a little washing up liqiud as a wetting agent.
and if the soil isnt a light mix there should be enough food in it to last 4-6 weeks.

Sounds like good stuff theMycorrhizal fungi works well for breaking down micro nutrients. dont over water in soil let your pots go some what dry before watering lift them feel the dry weight and lift again to feel the wet weight. you will figure it out in no time. throw some live worms in there.

If you use chemical salt nutrients in that soil, you're in all probability gonna kill off the mycos. It's the mycos (and bacteria) that break down the organic ferts into a form that can be assimilated by the plants. All organic ferts are basically decomposing organic matter.
If you plan to take advantage of the real benefits of the soil and it's amendments, read up on organics. That soil/nute combination should last at least 3 months. When I mix my soils, I mix them as a flowering nutrient soil, upping the N during the few weeks I veg the clones. As time goes by, you can add organic nutes by topdressing, foliar feeding, and by brewing organic "teas". All in all, a very rewarding experience.