Contact @Selena Walsh and @Scott Jackelen, they have operated many STRs and also work with clients in managing STR properties on their behalf. 

@Dax Gurr my guy Brad would be great fit for your operation.

I've asked her the simple question of whether she's interested in seller financing and her answer was no, but we didn't get into any further specifics on the topic.  

Please click on the links, give them a read, and share your thoughts in the comments.First is a post that I feel will help not get overwhelmed with the amount of info that is here on BP:https://www.biggerpockets.com/blogs/5868/52761-the-simple-guide-to-getting-started-on-bp The second is a post that will help get you focused with your real estate investing goals:https://www.biggerpockets.com/blogs/5868/52743-im-new-to-bp-any-advice-would-be-appriciatedThe last one is a post that will help you choose an “investor friendly” real estate agent.

As a simple example let's say you are raising $500K from 5 investors each investing $100K. 

Simple stuff Im sure, but being new to multifamily, Im lost on a couple things.

Simple answer. 

You could be missing out on a lot of deals if you are using 50% for expenses and most places in your market are operating at much lower.Also, if you have built a relationship with mortgage broker, you can send them a deal you are working to get more accurate # as well.

Seems simple enough to do online these days, but having an attorney help you on the first one makes a lot of sense.

When we make a real estate purchase, we often pay for the down payment from our own funds (equity in) and use business funds to pay for the improvements and operation costs.