Merged mining scrypt coins I've been reading around the last day or so on merged mining for coins, in specific scrypt coins but there seems to be conflicting answers, can someone let me know which of the following is correct

a) To merge mine coins they need to be specifically designed to merge mine from the start

b) You can patch a coin to merge mine (if so does the official release have to be patched to accept hashes from different blockchains or can you patch the coin yourself with auxpow to merge mine, will this not fork the blockchain im mining? ) 

c) This can be implemented by a pool, who submit the pow to multiple blockchains?
a) no need. you can fork your chain with the new chain-id at any time. but the wallets have to know the point of fork. The spanish coin pesetacoin forked the chain  near block 32000. and has no problems.

c) there is (at least) one pool mergemining with 3 main chains (you have to choose one) and 4 aux chains (pesetacoin orgcoin hutercoin and usc) have a look at http://manicminer.in