My understanding is that Palace only needed to buy 6 of the houses in the south corner to facilitate their stand redevelopment. They are building immediately to the north of the remaining houses, so daylight/ sunlight and Rights of Light are manageable.
We would need to buy many more than that to facilitate a new Witton Lane stand of the same scale as the current Trinity Road Stand - at least 20, probably more. The new stand would obviously be both deeper and taller than the existing structure, which would impact properties to the north in terms of daylight/ sunlight and Rights of Light.
Negotiating with 6 individual owners is obviously much easier than negotiating with 20-30. I'm not very familiar with the CPO process, but my understanding is that only a public body can exercise CPO powers, and only when there is a compelling public interest in doing so. The fact that Villa Park is privately owned, and not even by Villa, would probably complicate matters.
Liverpool's Main Stand redevelopment is a better comparison than Palace IMO. My understanding is that 150 houses to the north of the stand were demolished to facilitate this. I don't know the details, but I think the club were heavily criticised for how they gradually bought properties as they became available, and effectively ran the area down. If the CPO process had been possible/ appropriate, then it would presumably have been used here instead.
It might not be entirely necessary, but to keep properties at least the same distance from a new Witton Lane Stand of the same scale as is the case with Liverpool's Main Stand would require houses on both sides of Holte Road to be demolished.
