Feet should come together right at the end, just before contacting the floor.
Anyway, I'll take a look at the video and comment as I go. Stream-of-consciousness first, then I'll try to break it down and make suggestions on what to focus on.
-Hurdle is too high; it should be low, long, and fast
-Lunge upon landing the hurdle should also be lower
-Timing of the turn in the first phase of the RO is excellent -- you avoid the extremely-common mistake of turning early, well done.
-Hand position looks correct from what I can tell
-Bent knees while your legs go over the top make it much harder for you to pivot efficiently; straightening the legs won't just make it look nicer, it will make a noticeable mechanical difference as well.
Regarding your drills:
-The roundoff to the knees drill.... I'm not sure it's helping you where you're at right now. It's a good drill for certain aspects of the skill, but I don't think it really addresses any of your issues that well. I'd leave it out for now, possibly come back to it as a backhandspring/snapdown drill down the road
Alright, so as for suggestions, the first thing I would suggest is a TON of cartwheel-step-ins, both from fall-step and from knee lunge. Do them on a line, make them fast and powerful, and focus on straight legs going over top and also on the landing position. When you finish the skill, your arms should be right around horizontal (not vertical, horizontal), with your head between your arms, eyes on the floor in front of your feet, upper-back aggressively rounded. You may have too much speed to hold this position, and might stumble back or roll back to candlestick afterward, and that's fine; controlled landings aren't the goal at this point.
Are you working with a coach, and is it somebody strong enough to spot you? If so, I recommend training standing backhandsprings; imo, standing BHS is easier than a proper roundoff, and should generally be learned (or at least drilled) before the roundoff if possible.