Sam,
What is your reason for wanting to invest in Oklahoma and not where you live? Have you considered other markets besides Oklahoma? I can't answer all of your questions, because I don't know the Oklahoma market, but I can answer a few:
2. Is it risky/or safe for someone out of state to invest in Oklahoma ? Investing out of state is always risky. That doesn't mean it can't be done. You need solid "boots on the ground" to invest out of state. Without them, you're toast. You need a quality handyman crew and/or a quality contractor for rehabbing and/or fixing issues that come up. Someone has to live in the area to maintain the property or fix problems that arise. You also need a quality property manager as well. I tell investors that you can buy the best deal on Earth, but if you don't have solid property management, you have NOTHING. A bad tenant can take your profits down in a heartbeat! So make sure you have a solid team. It took me over a year to find a quality, honest and fair priced contractor. Having a solid and competent realtor that deals with investors, is also a very good idea. They know the market and can help guide you on where to buy.
5. Do i need to own an LLC ? No, not for the initial purchase. I'm NOT an attorney, but my suggestion is, that you put the property into an LLC; sooner than later. This will protect your personal assets, should something major arise. You can put the property into an LLC at any time.
6. Do i need to hire a PM to handle the property ? I strongly suggest you get a PM, (property manager). It's difficult to manage from a distance. PM's typically have handymen that can fix small problems that might come up. But be sure to ask them about how much they charge and what their procedures are, when something comes up. I don't know what fee they charge in Oklahoma, but in the Illinois market, we're between 8 and 10% of the rent.
We have investors from all over the country, only because we provide them with the boots on the ground they need, to invest out of their state. See if you can find a solid company that does that, in the area you're looking to buy. I would also suggest that you stay under maybe $100k for your first purchase. Get your feet wet and learn the business and how it actually works. Then once you have experience, you might want to "step up." I don't know the prices of duplexes out there. But in our area, we can get them for $110k or less.The rents are typically higher than an sfr, but so is the maintenance and in particular, the rehab costs. You need to take those costs into consideration before buying. Also with a duplex, you may need to hire someone for lawn maintenance, snow removal and garbage pick up. Those costs all add up. However, some investors give one of the tenants a break on their rent, in return for snow removal and lawn maintenance. A PM company may be able to provide those services as well. Unless it's different in Oklahoma, typically, the landlord pays for the water on a duplex, so keep that in mind.
I hope this helps and good luck.