I would like to know if, excluding genetic reasons, as much muscles I have I'll live longer and avoid more disease.
Correlation - two events happening together (like observing if carrying lots of muscle and living long go often together) shouldn't be confused with causation (hyphotesizing the more muscle you have, the longer you live).
High protein, higher calorie diets, typical to people that carry lots of muscle, add strain to your liver and kidneys. Lifting heavy and often pushing the boundaries of your capabilities, leads to injuries and decreased mobility in the long run. Heavy lifting needed to build lots of muscle, forces high blood pressure.
If lifespan is your goal, regular exercise, healthy unprocessed food, plenty of sleep, avoiding injuries and stress and being generally happy is the way to go. Many of these factors are also necessary to build and carry more muscle - you can't get big and lean without living rather healthy (although "healthy" is very relative term). For some people, being muscular improves their self-esteem, which improves their lifestyle, happiness and this could have a major impact on life. But even if there is data to suggest that there is positive correlation with lifespan and amount of muscle you carry, it still would be just a correlation. It wouldn't mean that the muscle itself is somehow making you live longer.
In fact many of the most muscular people in the world - like professional bodybuilders and weightlifters die very young (30s to 50s). Needless to say there are other factors involved (like drugs) but compare that to professional swimmers or skiers or just people who are just light, live actively and not carry significant amount of muscle. It draws a different picture.