Hi nadeephussi - you've got a lot to work with in that profile and we're feeling guardedly optimistic for you.
To answer your specific questions:
1. The prior admit to bschool doesn't count as an academic achievement and actually we're not sure if we'd even mention it anywhere; it could just raise questions from other schools about why you were applying then and why you didn't follow through (probably not a big deal but you don't want to have any "issues" in your application!)
2. You should definitely try for Wharton, they have a big class and not as cutthroat as HBS, plus they have a strong energy program. You should also definitely try for any of the others you listed if you're very inspired to do so - you have the qualifications that says you might make it. It all depends on the execution of course, and there's a lot of variables that we can't know - and these apps are all a LOT of work. If you're serious about HBS you need to get busy!!!!!!! You totally should not try to do their essay as your first application project. We'd also encourage you to try for MIT, you have a lot of stuff that makes us think that might be a good fit, just based on this cursory review. Their energy program is also strong.
3. On your 7-month gap, you definitely need to explain this somewhere in the apps. You need to tell the adcoms what you were doing during that time. The average grades are not great but we're not overly concerned with them; you've been out of school a long time now and the GMAT is solid.
We wanted to specifically comment on the thing that stood out for us: That experience during the Indian power failure looks like it might make for a good essay topic. The challenge you'll have is in elevating your profile beyond "just" the engineer - you seem to have enough going on that you'll be able to do so but it's something that's difficult for many with your profile. Your shift lead duties are good but maybe not enough (leading a shift isn't the same as
leadership in the broader sense of the word).
We're seeing a lot to like in this profile! Let us know if there's more we can address for you - you seem to have the raw material to make something happen. We're not saying you're gonna get into HBS

but you should be able to land a spot in a good MBA program, if you play your cards right*.
EssaySnark
* meaning, if you do a good job on the essays!!!