Hmmm. There's no wiggle room if Ralph the friendly alien and his pals make a visit though.
Right now, religious folk can point to all those answers we don't have, and claim that's where their god is.
Those questions would all be answered pretty fucking toot suite if Ralph turned up, given what he'd have to be capable of, to travel the distances required to come say hello, and the understanding he'd have to have of the construction of reality to accomplish it.
I mean, there's always the argument of panspermia and our ancient and contemporary God myths being essentially multi-millenia long examples of the telephone game.
Think about it. Even in ancient Egypt, things like the Sphinx and certain pyramids were already ancient structures. Whose to say ancient humans or human analogoues weren't placed here through dumb luck by way of meteor contamination or, purposely by a higher evolved species. If you're digging into the unknown, both known and unknown unknowns - then the possibilities are quite literally nearing endless.
What if Earth is just some penal colony or test ground, or second/third/hundredth planet that our actual cosmic predecessors decided to dump some of their population off on? It sounds crazy, but we know about so little of the universe, even that of the portion that light allows us to see. Earth could be just a piece of humanity. Similarly, if you had one Master race, who spread themselves out over the universe for lowball thousands of years, they'd end up evolving differently, which gives some credence to the fact that the most commonly reported "type," of alien is the Grey- a humanoid shaped bizzare little Grey asshole with no muscle, a short stature and a large head. You know, essentially what the human race is evolving into. Larger brains, lack of distinguished race, becoming shorter and less built as time and dependency on technology increases.
I dunno, dude. I've never had one land in my back yard, but I could see how you'd put together all of the pieces into a believable scenario, which is where everything starts. Believer or not, I think it still requires transparency and research, because the quickest way to get someone to stop theorizing is to prove, 100% beyond a shadow of a reasonable doubt - the theory is nonsense.