Releasing "fair code template" would require probably one template for each PoW algo (scrypt, sha256, ...) and would require someone to maintain it and merge useful changes from bitcoin, litecoin and other coins ... potentially quite a lot of ongoing work.
I suggest rather just publish some guidelines with explanation why to stick with them, like:
your initial difficulty should be set between X and Y.
This would be harder to tune, but I'd say the really absolute minimum would be so that with original dev's mining hardware the coin would be mined at half speed, or more if the coin is preannounced, even more if massively hyped.
OTOH, if the diff is set too high and none of the initial miners can't find a single block in an hour, then the coin will probably fail horribly too ....
your retarget should be small enough to mitigate any instamine attempts on coin launch (if too many miners join to push block times to few seconds, the coin should adapt quickly), or to avoid coin being unmineable if to many miners leave for another coin (remember Catcoin?
)
your block times should be reasonable. I'd say 30 seconds minimum, unless you greatly improve the protocol to allow smaller times without excessive forking
(6 seconds like 1st iteration of Nutcoin is not a good idea, as it resulted everybody mining millions, but unspendable, as the wealth was only on their own fork of the chain)