You have the rights written in the deed at the land office. No ideas why there are people like you giving completely unappropriated and unwanted and completely wrong advices. Must be your name ....
Get a standard banking app. As far as I know: you can register an credit card with it (no need for a bank account). - no idea how much that would cost, but a 3% fee is absurd expensive.
Yes, and then you show the visa. Sorry, no idea what you want to argue about.
The only visa where an onward ticket is required is a single entry tourist visa. Which at the moment no one is handing out, as most countries fall into visa exempt and you get a 2month free stamp.
So, if "what ever airline you are using" is asking for an onward ticket, when you actually have "a real visa", they are in mistake. And it should be simple to point that out at the airport.