Beans and legumes do not cause leaky gut. There's a lectin theory of food that circulates every forty years or so from people with letters at the end of their names that want to sell stuff. I hear your pain, though: of the 37k+ books on health and nutrition on amazon, very few are reliable. I'd suggest material from nutritionfacts.org and the knowledge-army there. (And from a preventative medicine standpoint, not only should you stay away from social media for information but it's highly suggested that you delete all social media accounts and do the same with anyone you love. The more you use them, the worse off you become.) It's fairly simple, though: the closer you can get to a _whole_ plant habit, the healthier you are. Whole means nothing bad added, nothing good taken away. You are correct about refined flour products -- all the good stuff is stripped out before they fortify it with junk. The meat alternatives have chemistry sets added which are great if you're a curious person with a McSausage habit, but not ideal for long-term health investments.
There are only three necessary supplements (two depending on which part of Earth you live on): B12 sublingual, D3 (not necessary if you're on the equator and getting a lot of sunlight), and the algae-derived omega 3 you're already getting. The multivitamins with antioxidants are ineffective at best and harmful in some observations. Get your nutrients from plants. There's a variety of things going on that science still has barely scratched the surface on and people can't put that into a pill yet. A good metaphor is the principle trumpet player of the London symphony: taking an antioxidant out of a plant and putting it into a pill is like taking the second valve out of the London symphony's principle trumpet player, handing it to you, and saying "There you go! The London symphony! Don't you feel better?!"
There are no good nutrients in eggs.
"You need to put some meat on your bones!" is just code for "Why aren't you fat like everybody else?" The balance of evidence suggests that being lean is the most healthy thing you can be. What other people perceive as normal is broken and there's nothing you can change about their perception. Be the light. Your kids will get taller the more plants they consume as early as possible.
