A 97...
a) I don't think so, other than weapon supremacy. There are probably other feats or class features out there that do something similar (I think there's one for daggers, but can't think of one for slams)
b) If you're using some sort of class feature or feat that increases your number of attacks, then simply follow those rules as applied to your slam (assuming you are using your slam as a primary attack). The only difference here is that you don't get to make your iterative attacks since the slam is a natural weapon.
c) DM territory here
d) By default, primary natural weapons deal +Str damage. Secondary deal +1/2*Str. In a few cases the primary will do 1.5*Str, but those are specifically mentioned (and are usually only bites or gores). If you are using a weapon as a primary and using your slam as a secondary, then it will only do 1/2*Str.
e) It's usually only the unarmed damage. I think for monsters that have improved grab, they can deal the damage of the natural weapon which triggered the improved grab (can't remember the source for this though).
f) I can give a yes and no answer here. Technically the feat give your natural weapons the property. However (and I can't remember the source... Savage Species maybe?) if a creature has damage reduction, typically it's natural attacks will be able to overcome that same DR. In this case you have DR 2/adamantine, so you should be able to pierce that DR. This is arguable though, so check with your DM.
g) Yes, you threaten with your slams. No, you can't trip with your slams.
h) You are not actually wearing armor, but you are considered to be wearing one for the purposes of class abilities and whatnot. What you can and can not benefit from however is a debated point. People have argued that the barbarian example is due to poor editing, or people have argued the other way that the intent was for the barbarian to be able to recover his speed. Yet another "ask the DM" kind of thing.
i) Technically no. It's not actually armor, so you can't put those add-ons. Armor Enhancements are specifically called out as an exception. That said, it's certainly reasonable to do, but given that there are feats to do so, it's probably against the designer's intent. As for fortification, yes it would be redundant.
j) Can't really think of any good ones off the top of my head (check my index though; there might be stuff in the polymorph section). Constructs typically have high hd, but there might be some interesting warforged variants in the lesser Eberron splatbooks. I know there's at least one flying one somewhere.
bonus) Because you're taking a race which already breaks a lot of rules that the designers didn't entirely account for, you're mixing in natural attacks which are also poorly documented, and then you're throwing grappling on top, because apparently you're a masochist.