This and the Argonian are surprisingly the only two of this series that I could see that involve the evolution of bipedality.
Whether digitigrade ("furry style") or plantigrade (human style), the important thing about bipedal locomotion is that it requires a massive overhaul of the entire body structure, in evolutionary terms.
Let's consider the skeleton first. Obviously, what the legs connect to - the pelvis - must change, to support the changed leg position, and force from what was previously behind. That's a 90 degree change.
Because of the extra weight borne, the legs themselves need to be made thicker, heavier and more muscular, while at the same time becoming more columnar - the weight of the whole body needs to be able to rest through a vertical pillar of bone, not a zig-zag, or standing will require constant work by muscles.
The spine, which previously was a splendid cantilevered system, with head and tail balancing out the spine and creating a spring that could be used for great leaps and bounds, is now vertical, and under constant compressive stress - this requires bulking it up significantly, and making it far less flexible.
The forelegs are now free to become more flexible, though for this to have any significant evolutionary advantage, there'd need to be something like brachiation (walking while holding to branches).
The ribcage no longer ties running to breathing, as it won't be compressed at every step. The deep keel that ws once important no longer matters and instead a wider, flatter chest is better because it gives a wider grip and means you can cling to more stuff in an armload.
The fixture of the skull to spine needs to rotate forwards 90 degrees to be supported by the spine, and since it is no longer providing a counterweight to the organs, it needs to be balanced atop the spine. Looking from side to side becomes a rotation rather than a flexing of the neck vertebrae, which means rebuilding them and reducing flexibility once again.
Then there's the soft tissue.
Sex, which used to be a simple matter, becomes complex, as genitals move around with the pelvis, and the legs start getting in the way, as do the new buttocks, which are required to make any kind of sitting comfortable (though the tail could be co-opted for this I guess), and for storing the massive muscles required to merely remain upright while walking.
Internal organs, which used to be pleasantly supported by ligaments suspended from the spine, now sag downwards, causing prolapses. Muscles need to be moved around just to keep all that in place, but hernias still happen as stuff bursts through.
The heart, which used to only have to pump blood up and down a few feet, now has to handle pressure differences of perhaps six feet, and the legs require a lot of blood for their newly-strenuous work. The brain becomes subject to blackouts when standing up, so various filters, gates, and pressure sponges need to be developed to prevent that.
For all that to happen, there needs to me a MASSIVE evolutionary imperative to cause such large changes. There are various hypotheses about what happened to humans.
Some claim that we just sat under trees and needed to be bipedal to reach up into branches, or hang from branches, etc. Others say it was to carry things, citing tool use. Others say it was because the hot midday sun caused us to become bipedal to reduce our surface area to the sun.
My favorite, though I'm very biased, is that we went semiaquatic, and needed our hairlessness, blubber, and bipedality for wading and brachiating in flooded mangrove swamps. In fact, monkeys in such swamps tend to move around in exactly in this way.
For the Argonians evolving in the swamps, then, bipedality can arguably make sense. But Khajiit are a harder problem...