This is what I do. Its works well for me and I've tried to put it in an order so that the muscle group on the following day isn't too fatigued from what I did the day before etc (unless you want to a pre-exhaust set up). I tend to keep the big muscle groups trained on their own as they are heaviest training days and I don't want to overtrain/use up too many calories on these days, priority if you get what I mean. I also train the larger groups at the start of the week when Im freshest. I get legs done and out of the way as that is the heaviest part I train, and I save arms as something to look forward to at the end of the week. I throw in abs when i fancy it as they get worked enough from deads and squats etc IMO (unless contest prep or summers coming, ha). If you wanna bulk, abs won't really be a priority then (as they'll probably be slightly if not completely obscured by the bulking up of weight). Keep clean calories high too. Look at GoPro's P/RR/S training program, thats helped me when I throw that in every few months or so
You should probably try and throw in some leg extensions and curls if they don't bother your ankle; it's better than nothing.
Dead right, coming back from any injury is an ass, especially legs. These are muscles you don't really wanna lose to much size and strength from. Try and hold on/maintain what you have with leg exercise like the ones mentioned and again, high calories+protein to suport them