Unfortunately, given the way the engine is structured, this is not possible. The way it works is scenario data driven, not executable driven, so not even a patch will be able to do it.
For an alternative start, one needs to define a completely new set of TF data, with new Ship content, and with Airgroups adjusted to new missions, and with LCUs (and new LCUs) in the right place and re-identified to the new TFs and with new planning targets. And once a new scenario is set up with alternative-1, it is cast in stone, just as the stock opening day moves.
It takes maybe 2 or 3 days (weeks) to develop an alternative opening day scen, and involves substantial changes to the Ship, TF, Airgroup, and Location files. Yes, if you launch the game, you can change the destinations of all the “magic move” TFs (and do the clickfest for all the KB airgroups to change mission and target). But you can’t add LCUs, or change their planning target (you can, but it will go to ‘0’) without editor assistance.
If you have an opponent that trusts you, you can make a new opening day scen, give him/her some new intelligence (including a lot of useless and misdirective crap) and play it out. Remember, it’s only the opening day moves that are defined. After that, you can go boogie till ya puke.