Let the page be the AUTHORITATIVE source for that work. Ensure the URL has the ISBN, or if that isn’t relevant, the MD5 digest of the FLAC (for integrity checking). Would be good to have a standard for indicating authoritative URIs for digital works.
Make the page the PermaLink for the work.
That page (with the artist’s domain in the URL) is gospel for the work. Encode the page’s URL in all metadata for all files.
Bung metadata in the page’s HTML.
As for a tip jar “I would have gladly paid $n.nn for this, let me rectify that now”, yes, you could put that on this page.
Pledging is a matter of chipping in a small amount contingent upon the production and release of future work, either any work or a specific work. So you could have a pledge button on the artist’s page “I’d like to pledge a quid to you for your next work, hopefully to be released soon” (qv http://www.quidmusic.com). You could also accept requests, and create pages for frequently requested works not yet embarked upon “I think you could do a great rendition of song X, there’s $N from me upon that fine day”, or for your suggestions of things you could do “Yup, I think your ideas of doing work along those lines would be worth exploring, I’ll chip in 50 cents for that”.
NB Pledges are not tips or charitable donations, but commissions/bargains/purchases/patronage, the new deal: art for money, money for art.
Your audience wants to pay you – you do not need to charge them for ‘possession with intent to supply’ on penalty of copyright infringement with 5 year jail terms and million dollar fines.
Imagine all the people
Sharing all the world
You may say that I’m a dreamer
But I’m not the only one
I hope someday you’ll join us
And the world will live as one