Lots of great questions!

My answer is that this is very complicated, your part is very simple and easy.

Try this ref for starters.

Here is a link that might be useful: soil organisms

i heard that wood only takes up nitrogen when it was still green as in not dead like you dont want to try to burn green wood but you could make a momb fire out of dead wood

straw, hay manure will all introduce weed seeds. That said they are all good sources of organic matter. If the manure is fresh don't use to much. I am not a big fan of digging a whole bed, just lazy i guess. I would layer in the organic matter and i would probably then cover it with a nice looking mulch, just me. with manure and all that organic i would skip the fert. I probably wouldn't plant it until next year either.

"i heard that wood only takes up nitrogen when it was still green as in not dead"
pezelko

Actually just the opposite but that doesn't matter, brown's (wood, etc) need nitrogen to break down but that N is consumed by the soil organisms and recycled right back, no net loss.

"I am making my first hosta bed. I read on the American Hosta Society web site about tilling 12-18 inches deep. Then use a 3 part ratio - 1 part native soil, 1 part peat humus for water retention and 1 part pine bark fines for aeration."

This just silly dumb advice.

You can't effect the Ph of your soil in any significant way and don't need to worry about it.

Use the manure up to 3 inches then mulch on top, your choice and the chopped up limbs, etc are great.

Now, dig the minimum hole possible, add whatever layers of organic matter you have and mulch and you are finished, period.

I'm serious, it is that simple.

Try this ref for a while.

Here is a link that might be useful: Fertilizer