Yes, you are correct, she will need quite a bit of "doctoring up" once she is captured, possibly including de-fleaing, de-worming, and de-earmiting. It is not necessarily true, though, that she would never learn to trust you after the shock of TNR- especially if you are her only food source. I would strongly discourage declawing her, though. Besides the cruelty factor, you will not know in the beginning if taming her will be successful. If it doesn't work out and you conclude she is happier going back to living outside, this will then become impossible if she has no way to defend herself.