Here is a link to what the A.G. Russell website lists as "hunting knives" in their catalogue:
http://www.agrussell.com/knives-by-purpose-hunting/c/133/
On that list is an offering from WC Davis (
http://www.agrussell.com/wc-davis-handmade-knives/p/WCDhhh412GLM/) who has his own website from which I ordered my custom S30V Loveless-style drop-point hunter.
The list should give you an illustration of some of the variety of custom/handmade and production "hunting knives out there. Actually, there aren't a lot of puukko's on that list but they also qualify as "hunting knives" and are quite different (simpler?) in design from those you pasted above.
The pommel swell (and spur or beak) and hilt/guard are incorporated as a rest for the handle in a point-up or point-down grip to keep the handle firmly in hand and prevent the hand from sliding onto the blade or off of the knife altogether in slippery conditions (cold/wet/bloody/fatty). A rounded pommel is more comfortable on the thumb or palm in alternative grip positions and also won't jab you in the side when in its sheath (if mounted on the waste). A palm-swell is also a common handle feature, again catering to enhanced ergonomics. Finally, the handle & pommel also serve to balance the weight of the knife-blade, enhancing ease of use. For most users, a center-of mass on a well-balanced knife rests on the index finger at the top of the handle (immediately below the guard or ricasso), neither blade-heavy nor handle-heavy, unlike a chopping-tool where blade-heavy lends efficiency in performance. You may also notice that most handles have an oval cross-section, again allowing the handle to fit comfortably in hand in a variety of grips (eliminating concentrated points of pressure so as to reduce formation of blisters or hand fatigue) and not so round as to rotate easily on its own during use.
As handles go, the key features generally focus on security of grip and ergonomics.
The knives you pasted all sport either a withdrawn ricasso or are choil-less, i.e. the belly of the blade either extends far beyond the width of the ricasso or meets the ricasso without indentation - those are fairly specific design features, not common to all or even most hunting knives. Certainly part of the purpose of this extended blade may be to prevent the hand from sliding onto it from the handle (fulfilling the function of a guard), and to put the blade well ahead of the hand during slicing/cutting (as with kitchen knives), but it is also a feature allowing for a wider blade-belly with a smaller/more slender handle.
A wide belly allows for a more acute edge-angle and thinner blade on a thicker (stronger/more rigid) spine, and a more acute edge/thinner blade increases penetration/slicing which is ideal in skinning purposes... however, there are other attributes which optimize a knife for skinning vs. another purpose.
A wide belly also functions as a "paddle", used to lift or separate flexible materials once cut into layers (again, imagine a kitchen knife slicing bread or a tomato or carving a ham).
One could go on and on about the various design features (or flaws) or cutting instruments (we haven't gone into blade-profile or grind yet), but suffice it to say there is no set design known as the "hunting knife", rather a vast array of designs which serve a variety of users in specific and non-specific ways. Take you rtime, get to know the various design aspects of different knives, ask lots of questions

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, and find out what attributes best serve your purposes... and always keep an open mind as you never know what new design or technology is waiting just around the corner! Have fun!
(Oh, and keep in mind that all of the above is simply my own opinion based on my own reasoning and experience)