What you've laid out actually looks like a well laid out plan for your goal, so good job for that. I'll just throw my few cents in for additional tips.
Losing weight will certainly help you with pretty much every bodyweight exercise, however it's very important that you maintain most of the muscle you already have. Consume adequate protein (about a gram per lbs of bodyweight you have) and make sure you don't train fasted.
Weighted bodyweight movements are great for developing power, make sure you are progressing in some form. The progress can be increasing the weight, increasing the reps, or just the total volume that you can handle (reps x sets x weight). Also, it's very important that you understand that your body will recover from bodyweight exercises faster than major muscle weight training exercises (squats, deadlifts, etc). Therefore I HIGHLY suggest that you do these movements (pullups and dips) with a lot of frequency (at least twice a week), if you find that you're recovering ok, I would even increase this upto 3 or 4. Basically, with any sport, practice makes perfect. So if you want to do muscle ups, you MUST practice the two main movements, the pullup, and the dip, as often as you can, in a smart manner.
The assistance work that you listed are fine, but make sure you don't overdo them. For example, don't do negatives too often, as they are just a way to shock the muscle group, and overdoing them will set you back more than anything. There's actually a few studies of beginners working out with straight sets as opposed to shock techniques such as supersets and negatives, and the first group gained at least 30% more strength and size. So, just stick to the basics, make sure you get your pullups and dips down right, and do them often, you can add assistance work once or twice a week.
As a final note, the grip that you should be using is what you are most comfortable with, it is as simple as that. Everyone's built a bit differently so one grip that works for someone might not be the best option for you.
To conclude and make sure you really understand what I'm trying to say. If you want to do muscleups, you absolutely MUST master the basic fundamental movements first (dips and pullup variations). Do them as often as your body lets you, at LEAST twice a week (maybe once with weights for strength focus, and once focusing on high reps for muscle size and endurance). DON'T rely on the assistance work, practice your sport; do your pullups and dips and do them well, ONCE you stop progressing in these movements, find out where your weaknesses are and incorporate the assistance movements accordingly. For example, if you find out that as you're doing your pullups, your grip is slowing you down, THEN incorporate some dead hangs and grip work. You know the cliche, a chain is only as strong as its weakest link. If you're finding that you can't push yourself up when you get to the top, work on overhead press, work on getting stronger triceps with DIRECT TRICEPS work, close grip bench, anything...
I will say it once again, if you want to do muscle ups (i.e an explosive pullup into a dip), then you must do exactly that. Pullups and dips, as best as you possibly can as often as you can. It's the same with any sport, if you wanna get better at golfing, you go to the pitch and you practice your swing, you play golf!
