1).
Either single family or multi family can be a great investment down here. I personally think if you can get into a duplex you definitely should as rent prices have gone way up over the past year which will obviously help paying the mortgage and have future income potential.
2).
I have purchased my last 2 properties off of homesearch.com which were both pretty good deals. Multi family properties are not on there very often so you'd have to check the MLS, but with such a competitive market right now the MLS is very slim on good deals. However once schools start back up the competition will drastically decrease and deals can be found again starting in October.
3).
My wife is a realtor and she has worked with multiple investors. She is comfortable in that world. I can provide you with her contact information if you would like. Send me a PM if you are interested. I would recommend interviewing several realtors and finding one that you are comfortable with. Again MLS deals right now are very hard to find at least until October.
4).
I am new to bigger pockets so I cannot give too many details for this.
5).
I like investing in A and B areas so I focus in the Puyallup, Sumner and Bonney Lake area. If I were going to recommend an area near the base, it would be to look in Spanaway where I Have seen some well priced properties. You will need someone to help in that area as there can be some sketchy locations, but it is convenient to the base and improving as an area.