Nobody talks about casting an indie movie for a 1st time director, because it's the 3rd rail. You can't talk about actors who passed on the project without looking like there's something wrong with your movie. And there is. It's you, the 1st time director. You're the boat anchor.
Can you make a movie with no-name talent? Yes, you can. But you may have a hell of a time selling it. And it STILL costs a lot of money. Anyone who tells you $30-50K (where nobody on the cast or crew gets paid a living wage) isn't a ton of money is rich, full-stop.
Remember: a scrappy low budget movie costs about $200-500K. The amazing low budget sci-film THE VAST OF NIGHT was $700K. That's a SWANKY HOUSE bought outright, not on a 30 year mortgage. And that had no stars.
An indie that has a chance of recouping its cost needs faces for the poster that make people say "oh yeah! I know her/him!" To get X budget, you need Y actor. Smart producers want to have the movie paid for by pre-sales. So they have lists.
The best actor for your film might be the lead from a similar film, but they're not going to do YOUR film (you're a nobody, remember?) for NO money. So you need to think creatively. Maybe the 2nd actress from a smart TV show that not many people saw NEEDS this role.
But how do you get to her? Producers with a track record. Which means they HAVE relationships. Or Casting Directors. Who need to be paid for their time.
But let's say you have a producer with a track record who supports you and a casting director who's helping you. They still have to pitch why they should want to work with you, the first time director. Which brings us back to The Problem: You.
Because there's no money, and this is a passion project, the actors' reps will put it low on the priority list. Which means that it takes around 3-4 weeks to get a response. This is why scripts will be optioned for 18 months. As Tom Petty said, "the waiting is the hardest part."
I don't mean to discourage you, but you need to be realistic. Know that on paper, you're a boat anchor. But also know that you're one step away from being the shiny locomotive. You just need to build a team that believes that you are the little engine that could.
The best way you can circumvent this is make the coolest thing you can make for what $ and resources you have. A short. Then go submit it EVERYWHERE. Go to all the festivals - especially the LA ones. Meet the actors who show up (they do). You're equals there. Future collaborators
Write to THEIR strengths - or for the roles they wish they could do, but nobody gives them a chance (sound familiar?). Give them a producing credit. Have them suggest their friends who would be ideal. Now you have a cast full of "I know them!" even if they aren't "names."
And I know this seems contradictory, but your biggest mistake is making it about YOU. This is a relationship industry. It IS who you know, but who you know don't have to be big shots or wealthy. So make it about the project. People can get onboard a project they believe in.