The thing I see with your svj is, youre bending at the BACK and extending it FIRST, then you start to extend the hips. If anything thats causing you to lose some contribution from the tightness and reflexive action you would get out of the stretch reflex. You can still have plenty of torso lean and jump well, but it should stay relatively stable and not extend at the low back before the hips and knees start extending.
On your deadlift youre just not getting your back position "set" well enough before you begin pulling, it almost looks like your relaxed in the bottom. Squeeze the chest up HARD, but you dont need to drop your hips too far down before you begin pulling, youll just end up with a higher hip position anyway once you put a heavyish weight on the bar. If youre really certain you need a more upright position with your squats and deads, get you some weightlifting shoes. They will change the mechanics by themselves without you having to do much.
A good drill for the running jumps off two legs, and achieving what youre talking about with the plant leg is to start about 6-8 feet from the basket with both feet together. Focus on taking a very big and powerful step into your plant leg, really emphasize that leg reaching out and loading it. Dont worry about the jump height at first, just focus on reaching out with that plant leg as explosively as you can, then jump. Once you get this down and can jump well with it, progress to a 2-3 step approach with the same mechanics. After that, using a full run up will be much easier and form will be more stable at higher speeds. When doing that drill one thing is to not think too much about it being a "two leg" jump, but really really focus on that plant leg, the swing leg will come through and do its thing pretty naturally most of the time if you get the plant leg working well.
try that squat stretch I linked, that will likely help you as it really hits the soleus well and not just the gastroc. Once the knees are bent (like in a squat, dead, jump etc.) the soleus can really limit rom at the ankle and that stretch can make a big difference if you progress it and use it frequently enough.