Yes do the 8-10 reps, but that shouldn't be to failure. You want to feel like you're working to around 90%-95% of failure, as going to failure all the time, uses more energy and potentially has poor additional rewards attached.
2,000 calories is not a lot. If you split it into 6 meals with roughly equal calorie amounts per day, then around 333 calories per portion doesn't seem too bad.
Carbs before a workout is always a good thing, as long as you're not eating too many, but carbs after is always good too and complex ones elevate bloodsugar and muscle glycogen levels, so things like bread, pasta, beans, rice, mushrooms, veggies, etc are good for recovering with, but protein helps too, as about 40% of protein intake can be converted into muscle glycogen and insulin can help this and by triggering insulin production through carb consumption, you can recover muscle glycogen moreso with protein in the mix not just carbs and therefore you should be able to generate more stored energy.
1,200 calories as an intake for losing weight is not reccomended. it's about 2/3 of what sedentary females need let alone active ones and if you don't get enough nutrients in the diet, that contribute directly and indirectly to bone health, I.E. Calcium, Vit K2, Vit D, Vit C, Copper, Magnesium etc, then you could promote Osteopenia, (thinning bones) and this would increase the risk of hairline fractures, or possibly worse than that, from the bones possibly becoming intolerant to cardiovascular impact shocks, or the flexing of the bones caused by weight training.
This would depend on what level of such nutrients you consumed, in that 1,200 calorie a day diet and their cumulative effects on bone condition.
The 2,000 calories a day approximately, would be more beneficial and not least for consuming more nutrients beneficial for cell protection, immune system function, cholesterol management etc.
A large part of the calories could come from sources of good fat, particularly things like edible oils butters and spreads, nuts, peanuts, avocado, flaxseed, omega 3 eggs, (chickens fed some flax), soy products like soybeans, tempeh, tofu, edemame, nattokinase and miso, low fat cheese and olives, as fats contain 9 calories per gram, so if they contribute around 30%-40% of the calories, then you'll be able to have a good chance of consuming your 2,000 a day.
You body may take time to adjust, so you may find a slight amount of weight gain is possible, depending on the difference between current calorie intake and increased intake, but after about 1-2 weeks or possibly more, you should settle into a new metabolic rythmn and coupled with the exercise you should start moving in the right direction.
Hopefully that all makes sense
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