Oh, right, so you expropriate their property. A Mugabe-style redistribution of assets, excellent.
1. Are they compensated for this?
2. If yes, at what valuation?
3. Do you do this only to this club? Just to the current PL? The whole pyramid?
These points are discussed already - the most significant point (personally) isn't fan ownership financially, but a casting vote on defined key issues affecting the club - commercial, financial, competition, governance, etc. I'd be happy to build into that a structure for how/how much the owner can profit from the club - it's unrealistic to expect them never to take a dividend.
In short; 1/2 - yes, if necessary, but the point isn't to dilute the financial value of their holding.
3 is a good point; as already stated, more than just this club. It needs to be the PL (at least), to feed up to making meaningful changes at a competition/association level - on FFP, wages, sustainability, 'fit and proper' rules, etc. That probably needs to extend into the EFL, to some degree - or at least be signed upto by clubs as they seek to gain promotion, much like stadium standards are on promotion.