Hi Kurt, welcome and good luck. First, I'll note that activity on MC23 forum has slowed because they've moved onto MC24. I do think starting with a fully mature version like MC23 is best for newbies as you don't want to be fighting bugs while you're trying to understand computer audio and MC "the beast" of all media apps. If you're still unsure of your purchase after your eval, you might be able to trial a different version for another 30 days or ask the admins for for an extension. How is your eval progressing?
I'm a novice user after 4 years, here're my answers:
1. Yes! MC can certainly change or delete your files! There are good menu prompts to help avoid accidents, such as "are you sure?". Do pay attention and you'll probably be fine. Anything that says convert should be avoided until you have more confidence.
2. See above, not sure how to prevent it other than backing up your entire file system and library. We should all do that, seriously and there are good forum threads on how.
3 and 4. Yes, I do this for sound quality and control.
Tools > Options > Library & Folders . AutoImport
5. Sweet DAC! You may find MC to be your ideal home for all the flexibility dealing with many file formats. I saw something about ASIO on MC24 forum for MAC, might try asking your future questions there and noting that you're trialing MC23. I don't do ASIO for Mac and plan to switch to Windows or linux soon, again for SQ and support.