Realtor is usually someone who sells houses or condos. If you mean the same as a real estate agent, then yeah, they're typically the same thing. Technically there can be differences, but you almost never need to worry about those (usually who owns the agency, and if everyone is licensed on their own, etc).

For the follow up, sure, you can try. I've found apartments without them before. It's just a pain in the ass filtering out every single agent/broker listing.

And for the final part it's worth noting you don't always have the choice if an agent is involved. Tenants can and usually are required to pay the broker fee, even if it's the landlord's personal broker. No one likes that as a tenant, but unless you want to start a ballot innovative or something then you'll either suck it up and pay the fee if the apartment is worth it, or keep looking for that ideal apartment without a fee.