How viable are "photography templates" where a professional gives the
exact settings to use in a specific set up...to allow noobs to produce
high quality photos?
That sounds a lot like the "scene" modes built into most cameras. The camera evaluates the scene and chooses settings using an algorithm designed to produce a nice photo. Having the camera do the work is probably a lot more practical than expecting people who don't know how to choose their own settings adapt a set of predetermined manual settings to their situation.
Here's an analogy: I have a friend who is a wonderful musician. What if she could tell me what keys to press on the piano, and when to press them, and exactly how hard? Could I then play a song that sounds the way she'd play it?
Maybe this one is more fair: A famous pastry chef creates a new recipe for chocolate cake. It's well received, and eventually people start asking for the recipe; she eventually publishes it in the NY Times. Hundreds of home bakers read the article and try baking the cake. For many, the cake turns out very well, because it is after all a good recipe. Is the home-baked version the same as a cake made by the chef? Probably not. The chef likely buys a certain kind of flour in 50 lb bags, likes a specific brand of vanilla, only uses the finest chocolate, has years of experience making perfect pastry cream, works in a professional kitchen with well-calibrated ovens, etc. Each of these details make a difference and are unlikely to be replicated at home. The recipe is probably even adapted to take many of these factors into consideration and still yield good results. But at the end of the day, the home-baked cake is bound to be different, and the best home-baked versions of the cake will be produced by people who've developed some skill of their own and can make their own small changes to the recipe to account for their circumstances.
I wish to take high quality headshots, but I have no access to professional photographers (but do have a decent dslr from friend). So I wondered - why not ask what settings work best in an environment I want to take my photos in, and just imitate what a pro would do?
I think that it's reasonable to look for a formula that will give you a better success rate than, say, just guessing. There are certain things we can say about headshots -- soft lighting, shallow (but not too shallow) depth of field, focal length somewhere between 50mm and 135mm, etc. But even given that, there are still a lot of variables that you should think about if you want to make a really good photo:
- What is the model wearing?
- What kind of facial expression suits them best?
- What, if anything, is in the background?
- Do they have a big nose, or a tiny nose?
- Are their eyes the same size?
- What is their hair like?
- Are they old and wrinkly, and if so, are they the kind of person who's comfortable with their wrinkles?
Your question is predicated on the idea that using the same great recipe over and over will always produce great results. I think that the reality of the situation is that using the same great recipe over and over can give you good photos if you are working in well-controlled conditions, but you won't bring out the best in each of your subjects and you won't reproduce the kind of results that someone much more skilled would get any more than I could follow directions to play a song the way my friend does.
There's a reason that beginners use the scene modes and more skilled photographers avoid them.