@Austin Osier, hey Austin, if you used to work for Nexus. Send me a private message, would be more than happy to discuss further. I am no longer with the company either.
Regardless if this is you or not, sounds like you are looking to Househack and have your tenant pay a portion of your mortgage. To be pre-approved I would start at a bank, one that you already have products with is a good start, another avenue is a mortgage broker, they can cast a wide net and because they don’t work at just one place they can get more options.
Depending your situation an FHA loan is a good option where you don't necessarily need to come in with the whole down payment yourself. If you like this idea and don't mind a little paperwork and can handle a fixer upper a FHA 203k loan is the way to go, you can borrow your rehab dollars and this applies to any single to 4 pled property. So let's say you buy a property for $100k and you want to put another $100k in rehab, then your 203k loan balance will be for $193k (200 minus your 3.5% down payment). Assuming you add value with your renovation you should be able to easily pull some equity in just a few years time.
Finally,since your already debating a duplex or triplex, go for a 4 Plex. Two reasons, firstly the management of a duplex or 4 plex is very similar, but you will get more rent money coming in. In a duplex if you live on one side and your tenant leaves or unit is vacant your carrying the whole mortgage. In a triplex or 4 plex, very unlikely all other three units will be vacant.
Then according to our 203k inspector ( one of the red tape hurdles on this loan) FHA typically doesn't like to see people moving from a duplex to a 4 plex. They like to see people move from a 4 plex, to triplex to duplex and finally a single family loan. The reasoning supposedly is that FHA is meant to help people attain the home ownership dream, not become an investment vehicle, so for them someone going from a 4 plex to a duplex means they are closer to the end goal of single family ownership.
Also remember that the rental income counts towards your income qualification, so if you think a 4 plex may be more difficult due to costs, its actually fairly similar. On the exit do have in mind that the buying pool for a duplex is going to be bigger, so if your thinking of selling in short period of time, the extra rental income may not make sense if that is your strategy.
Also I have a mortgage calculator that I had shared on BP previously that is set up for you to know how much you would qualify income wise, taking into account your front end and back end income ratio that your lenders would use, it also accounts for tenant income, if this is something you want send me a message.
Hope this helps!