An Interesting concept, and good luck with it
Re: 1) Well, the term 'cruiser' is now more or less covered by a lot of modern day destroyers, which weigh in as small cruisers in the old rating. And if this is a R.N. project, cost would be the difficulty.
Re: 2) I doubt if we could justify a new design based on the Falklands experience. While the testing of weapons on hulls etc. proved very useful, it was not a represenative conflict, as between major powers like the USA/USSR. Certainly, the Belgrano would have been a threat, if allowed near the main fleet, but she was sunk without any great dificulty, even using old fashioned torpedo's - though fired from a nuclear powered attack submarine. And it did serve the purpose of keeping the Argentinian fleet 'bottled up'.