Yes. The client have to validate every single thing in the block. Changing any component of the transaction will change the merkle root and in turn the block header. The block hash would be changed completely and as stated above, collisions aren't possible as of now. You can, of course choose to omit that transaction but that would omit the
Not possible. I doubt everyone would be with this, especially given that it would be considered a censorship (though it isn't morally correct to promote such content IMO).
Thank you very much for your response. I know there are people mining private keys with the LBC, etc. I wanted to see if the difficulty was on scale with that or less because the data that would replace the "bad data" could be random. Now that I'm thinking about it, it may actually be more difficult than that. Often my pre-coffee questions are answerable by me post-coffee, but I am not an expert and wanted to hear from a better source of information.
Yes, I also am not sure that I'd agree with changing the blockchain in any way, even if it were possible. Just exploring what is or isn't possible.
Best regards,
Ben