Hi! So my first recommendation is to use easier references for the animals. Remember the goal of the lesson is not to learn how to draw animals, but rather to use drawing animals as an exercise to learn construction. Worrying about things like foreshortening or harder orientations would detract from learning the primary goals of the lesson, and is an unnecessary challenge.

Of course, all of that being said, you are completely free to challenge yourself as long as it doesn't take away from learning the main concepts in the lesson. How I approached drawing an animal from 3/4 view is to not worry about foreshortening when drawing the individual forms, but rather capture that foreshortening in the size of the form relative to other forms.

For example, when placing down the major masses, assuming the animal is coming towards the viewer, I would make the head a bit larger than normal, and the pelvic mass a bit smaller than normal. Same with the legs, while there's no foreshortening within the leg itself, there would be a size difference between the two pairs of legs.

More important than the foreshortening I feel is capturing the correct angles (or degrees when it comes to the major masses and contours). For example, the ribcage and pelvic masses would be a lot more circular in an animal seen head on compared to in profile. In addition, most quadrupeds in 3/4 view tend to have their pelvic mass higher on the page than their ribcage mass (unless they're sitting down or standing). A contour curve across the middle of the torso sausage I've found is also an effective way of really capturing how the animal is oriented. Finally, don't forget that the contour curves defining the intersections between forms are also a great way to define the orientations of forms.

Hope this helps!