Cool. Now that's a concrete goal to aim for. Maybe look for a triathlon being held in a year or so, just to make the timeline more finite.
I hear you, but just keep in mind that you were out of the gym with a legit injury. Even if your diet slipped during that time, it's not like you were going along fine and then decided one day "Yeah, this whole 'being in shape' thing isn't for me, so I'll quit."
Gotcha. If you're working with a nutritionist, I'll leave all the diet info to them. Working live with someone face-to-face will pretty much always trump online discussion. But please do ask them about workout nutrition. A protein/carb shake taken before, during, and/or after exercise can have tremendous benefit.
Yes, you're trying to lose fat, but the positives of providing your body the nutrition it needs at that time outweighs any "negative" of taking in calories while exercising.
Fixed that for you.
Yep, I'd suggest slightly de-emphasizing the cardio in order to give solid attention to weight training. Three or four days of basic lifting, with some "easy-ish" cardio on those days and one or two days of only cardio, would be a very solid start.
If we're doing cardio right after lifting - always after, not before - 20 minutes of steady pace work is fine. Intervals are often too taxing when they're done right after weights. On days of just cardio, you can go harder, longer, or faster. (Thats what she said.)
For a basic weight training plan, check some of these:
(^ This might actually be the most appropriate for right now)
(^ I like this layout in general, but it'd be more appropriate once you've built/re-built more of a foundation)
This, done consistently, plus tweaking your diet via the nutritionist, will absolutely get you where you want to go.