Good answers above and some fairly long threads on almost the same topic (might take a bit with keywords but you can probably find them).
A few people here have done ab initio in a Mooney and thought it worked for them. They should be along shortly. I think that would be the minority. Agree most are better-served by a stepwise approach for multiple reasons.
"Gnothi seauton" as the old maxim goes, know thyself. I would further add that, if you have limited aviation experience, you might be very discerning in other respects but not really have a basis for evaluating your own ability to do this kind of approach.
A practical thing I would add to the above posts is: If you are an airplane owner/buyer you will spend a lot of time doing things that are not making you a better pilot. And you might decrease your actual aircraft availability vs. finding a good rental situation.
Spitballing out of the blue:
- get some hours of training, ideally through the pre-solo stage, make sure you like it
- get a medical (required for the above)
Yes a 172 or PA-28 is different than the Mooneys but the knowledge and skills will dovetail nicely into a foundation. You *might* have this same conversation about instrument training, but even then it's not a clear choice IMHO as a human factors guy. I think it's certainly too early to think that any time in trainers would be "wasted".
As to cost-effectiveness, it could go either way.
I'll leave the tax strategy to more knowledgeable people but if that's a determining factor for you, probably best to consult an appropriate planner early.
HTH
D