I will start looking out for 4 unit apartment to enable  me qualify for the FHA loans with a Down payment of 3.5%What is the % of my monthly fees on mortgage , taxes  and utilities if the apartment cost about $300000 and if the monthly rent of the 4units apartment is $3000  since I already know that %10 of the gross income go to the property management monthly and again.

For flipping, I'd strongly consider electing to be taxed as an S Corp, as it will enable you to pay out some of your profits as distributions, avoiding the 15.3% tax of self-employment income.

Really curious how/if to use arrived to supplement my investing strategy. 

It doesnt really matter if they are enabling you to make money.HA/VRBO keeps my calendar full and makes me money.

My goal is to create supplemental income through REI. 

If they're able to walk upstairs, they're able to handle your house.I ask this partly because I'm 64 years old, facing 65 real soon (and if I get one more advertisement for Medicare supplementation in the mail I'll throw up) and I'm managing my own two story 3/2.5 house just fine (along with 16 rental properties, including doing the yard work in empty rentals).

On the other hand, it may be simpler and straightforward to break into individual accounts, but that could become a headache as well.Ultimately, I think it all depends on how organized you are or want to be, and the best method you see to enable that.

I'm Currently in Direct Sales and want to supplement my income and heard real estate is a great place to do just that.

Some of them are WiFi enabled so I'm not sure how that fits in with your situation.https://leaksmart.com/

If it's agency debt, would you qualify for a supplemental loan instead?