sounds like an amazing plan - I would love to visit Meteora before or after my own upcoming Greece trip but didnt leave enough room for it! FYI I would say you probably want some rock-climbing practice for ANY place youd go climbing with ropes - id recommend a little instruction and test it out in one of your local climbing gyms. For hiking you'd be ok I think if you do that or enjoy it already.
re: local guides - I just did a quick google search on "Meteora Rock Climbing" and there were lots of options to check out. I think that may be better than this board since this audience is likely less into X-games (and probably not the typical target market). I love adventure travel but also love RS approach and try to combine the ideas when I can (so thats why Im responding since I didnt see any!)
good luck! you gave me more ideas to think about now too!