1) I have this one. It works okay, but the battery seems to die very frequently. 3) My boyfriend and I have a 600 calorie difference in our goals. We will generally have the same entree and different sides. For example, when we make curry I'll eat mine over veggies while he'll eat his over rice and have a pita on the side. I also skip the booze and dessert he'll have with dinner.
I have this food scale, though I use it for soap making and not food - it's SUPER accurate.
I use MFP like everyone else to track.
As far as husband and I go, we eat separate breakfasts (we leave the house at different times) except on the weekends, when I cook us both an equal calorie meal. We eat separate lunches (even on the weekends - I usually have a shake or something, he eats eggs/rice/veggies). And then I cook us dinner (but he usually gets a larger portion than me). If he needs more calories or is more hungry, he snacks. I don't unless I also have extra calories. We snack on different food (ex: I'll eat an apple and some peanut butter. He'll eat rice cakes).
For containers, I highly recommend something like this. I LOVE using it, especially to portion a large restaurant meal or something, and have leftovers the next day. If you don't wanna order on Amazon, you can definitely buy these at Home Goods and Marshalls.