Hi
I'm the current Access Officer for ASNaC at Cambridge, so if you have any other questions (this applies to anyone), feel free to send me a message and I will try my best to reply.
Current ASNaCs come from a myriad of backgrounds with almost every A level (or otherwise) combination possible. It is really the case with ASNaC that all that is being looked for is a curiosity for the subject and a willingness to learn
It's great to hear that you are enjoying reading up on ASNaC-y stuff! When I arrived I knew practically nothing, though, and I still have found the course really enjoyable. So don't let fears of not knowing enough deter you at all.
To specifically answer your questions;
1) If you acquired an A level qualification then it will still be relevant regardless of whether or not the specification has changed. It might not be particularly beneficial to spend your time re-doing something you have already done, either. However, if you are still curious about your subject choices I suggest you consult with a HE+ adviser or lecturer. The grade requirements are A*AA so as long as that is achieved/predicted in some way, this should still be fine.
2) Choose whichever college you like best ! In terms of resources, the ASNaC section of the English library has pretty much everything you need so you don't need to worry about that. Just pick one that you think would suit you most, personally!
I chose my college based on the prettiness of the library so it really doesn't matter (like at all).
3) You can look at past application statistics via
https://www.undergraduate.study.cam.ac.uk/apply/statisticsHowever, statistics don't mean everything, and the only way you have no hope of getting in is if you don't apply. If you are meant to be at Cambridge then you will inevitably end up here. BUT regardless, that is never a reflection of your personal worth.
4) While there is, unfortunately, a lack of ASNaC based degrees, there are some variations of English/history courses out there. If it is the English side you are more inclined towards, I suggest looking at the University of York, I believe Nottingham as well, and St Andrews?? Otherwise, Scandinavian studies is offered at Edinburgh and UCL though I don't think those include Old English. I am not certain, though, and so I recommend looking at their respective websites and having a nose at their courses in detail.
I hope this helps,
Nia