Any athletic endeavour (dancing, breakdancing, ballet, juggling) can be a potential aid if it fits/complements your style/reflex and movement patterns.
It’s impossible to nail this down, take the old argument about dancing:
Some trainers warn their pupils that dancing will bust your rythm and will make you predictable, others claim that on the contrary, it helps them remain lose and spontaneous.
Nobody can decide that for you, find out for yourself if wearing a tutu can somehow empower your overhand right.
Yep, having a big head is advantageous for avoiding getting KOd. This is because big bones have large muscle insertions, so the neck is stronger, which is one important link of a good chin.
A big wingspan is advantageous for most “brachial” martial exploits, while short arms can help project raw power for certain hooks, depending on technique, of course .
Most Combat Arts are heavily laden with unnecessary bullshit and dogma.
People will believe anything an instructor will tell them.
The pygmalion effect or similar psychological phenomena are very real.
Shaolin Monks had zilch to do with the evolution of combat sports.
Naturally athletic and gifted athletes tend to be more often the lazy ones, often parting with the sport when the first series of compounding injuries comes around.
Classical strength training has a minimal direct impact on punching and kicking force.
Really strong dudes are of course heavier strikers generally.
Big Dudes get affected more often by injuries, everything else being equal. That goes for practically all sports.
Training both sides pays off. As can hyperspecialization (a la Bill Wallace), but more in a restricted enviroment (Boxing in a ring as opposed to MMA).
Maritla Arts cannot be reduced to a handful of vague principles. It involves athleticism, a bunch of sciences, psychology and the ability to explore your own deep human mind-canyon of repressed animal instincts with open eyes.
Combat Arts are like a four-dimensional Diamond.
It has to many beautiful and complex facets to be grasped by a single human mind at one time. Pick those who suit you the most, try to perfect them and strive to learn more.