I want to add to what Andar said about number two. These days, there is virtually no guarantee that someone can finish a project without some kind of established track record. You can even see supposed "greats" like Tim Schafer struggling to deliver on his studio's projects, so it's not so much proof you need as a solid foundation.
Rapid prototyping is really essential in any kind of creative industry and saves tremendous amounts of time and money. Film, illustration, game development, prototypes are an everyday aspect of these industries and prove your concept works. Fortunately RPG Maker has an entire suite of placeholder graphics for you to sell a concept upon, and after you have a tangible demonstration you can begin scouting volunteers or freelancers. If you want to have a good roster of interested individuals, you need to make sure that your prototype very clearly establishes some kind of mood for your game and communicates concisely what it is about.
In addition to some kind of early prototype, a written concept of one or two pages is your second tool and chance to get prospective team members interested. You don't just want to hire people who will create material for you, it's more important to find people who feel moved by what you want to do. It essentially gives you team morale that maintains itself and ensures better synergy, because the emotional investment is already there.
Devil's Advocate time:
Maybe you don't need a team. Maybe you can run with this by yourself. Think about what makes the heart of your concept (what is important and non-negotiable, as opposed to superficial) and what's practical. Can you afford the extra time that goes into team management? It's stressful and a job in itself. Most people aren't good managers off the bat, and when you're struggling to just finish a game by yourself, it starts to slow down your momentum a lot. Free hands can come with a certain amount of drama and unpredictability. They're the kind of people that are nice to have, but not good to rely on. When push comes to shove, they'll only stick around as long as your concept and ideas strongly resonate with them.
You can also consider the alternative of cutting down on ambitions and creating lists of what you want to accomplish and circling the most important things. Try to have a backup plan where it's just you alone working on things that aren't overwhelming for your free time and experience level. Every piece of art begins with an idealized image, but no artist will ever tell you that their work came out like they envisioned. There's never enough time, money, or resources; so cutting back and lowering expectations isn't necessarily quitting or admitting defeat, it's restructuring in the face of life's unexpected happenings.
Whatever you choose, have something on the back burner. Good luck!!