B is BG bed. See pic above for idea.

If you plan a beach there are threads here on what and how to.

Yes put a few cedars around BG beds to aid in BG fry survival.

In deep water add vertical pallets to a pole or post. Can use one flat for bottom and 2 or 3 nailed end to end for vertical height. Like an upside down T with one on bottom and 2 or 3 end to end for height. You can attach limbs , cedars or pvc etc to the pallets for additional effect.

P = upright pallet structures.