The GB hatchets have edges that are optomized for cutting wood, therefore they do not have the durability necessary for chopping heavy bone as that would require too much performance loss on wood cutting. If you are going to chop thick bone you want to do it similar to cutting wood, chop at an angle and use a controlled stroke. Go through a joint if at all possible, which doesn't require any bone chopping at all.
Repeated hammer chops or flails into the same spot is a common bone chopping technique and is very difficult on an edge (it would be a great way to quickly dull or damage an axe on wood as well). As Jimbo noted, for that type of cutting in general, a simple cheap hatchet will do. You could put a more obtuse edge on the Bruks hatchet if you wanted, you would just lose cutting ability on softer materials like wood and flesh.
In regards to pounding, this generally means that you don't hit the axe with a maul which is a common splitting technique. I have never heard of axe heads being broken by hitting them with a piece of wood, or using them as a hammer/baton. It is possible of course, but based on what I have seen you are far more likely to damage something other than the axe, for example the knife you are beating on, few makers/manufactures would deem this acceptable. Its not going to be good for the lifetime of the head/handle attachment of the axe though.
Again depends on the magnitude of the task, I would not hesitate to use a quality wood working hatchet to drive in a small 2x2 stake, but I would not try to drive a 4x4 fence post into place with a felling axe. Consider the kinds of forces involved and how they compare to chopping. With the fence post driving that is easily much greater and thus beyond the scope of the axes design. However a small 2x2 tent stake isn't going to overstress anything.
Jimbo, the reason the axe could be used as a baton on a knife is than on small very dry and or knotty wood the axe will not split it easily under its own power. The alternative then is to beat the axe head through, usually done by reversing the axe and banging the poll on the splitting block. I have used the hatchet as a baton on a knife in favor of this method as the hatchet can hammer a decent sized blade with more control and thus doesn't require a splitting block. In general though I will use another piece of wood as a baton as it is easier on the knife, and I don't want to place unnecessary stress on the axe head attachment.
In general I would not split wood with a felling axe or hatchet because first off the bit and edge are not designed to take the stress and can easily be damaged on a bad knot as they are hitting it in the worse way under very high speed. Secondly the heads have a poor design for splitting with the strong hollow relief making the edge bind badly. It depends on the difficulty of the wood. I would split fresh pine of small size (2-4") with the wildlife hatchet, but I would not try to drive it through even a moderate sized 2 year seasoned piece of spruce. I'd easily beat a knife through that wood though, the edges on most of them are far thicker than the edge on the hatchet.
I have been experimenting with this lately (baton on knife for splitting) being curious after reading some of your comments about the thinner knives splitting wood and have taken some very cheap kitchen knives and split a great deal of 1-2 year dried spruce and pine. Interestingly enough, I saw no edge damage, unless I wanted to induce it by trying to beat the knives through hard knots with full force hits (very sloppy technique obviously). With a bit of care on the path chosen, the blades could handle it fine. These were 1/16" knives with 10-15 degree edges.
I should also mention that the GB people are net active, I have has several email exchanges with them in the past. They have contact information on their website. It could not hurt to drop them an email and get their perspective on the above two issues.
-Cliff
