1. I wouldn't use a dialer. Google STIR/SHAKEN, this is something that all major cell carriers must implement and ambulance chasing attorneys are hungry for cases. I was listening to a radio segment a few weeks ago and the attorney specifically said he's going after auto warranty, debt consolidations, and real estate investors.
2. Do you feel like you need one right now? If you don't know what they need to do, or what you would want them to do, you probably don't need one. If/when you want one, you can look on sites like upwork and find decent help for a few dollars an hour.
3. That's a great starting number, once deals start to come in and you have more working capital, you can scale.
4. I still to this day call hot leads on my own, I don't wait for anyone on my team to do it. So it depends on the lead type, if you're just cold calling lists, I would outsource to someone.
You're asking great questions! Let me know if you have any others.