That would at least lend a bit of predictability to your costs. 

That being said....we can not predict where interest rates will go.  5-7 years ago when we first hit 5%, no one thought it was possible for rates to go lower, and they almost hit as low as 3%.  

I'm not smart enough to predict the market.

According to banker, "Predicted strong growth for next 8 years, Everett next Bellevue", very cool.

I am also predicting I could get around $1,300 for each unit as a 1 bed 1 bath apartment with what I believe to be around 600sqf.

and 2 children still left at home, I need to develop a business that provides us a predictable, ongoing income.

Rent roll is 1% of asking price as it stands but I predict rents could be raised 20% without too much resistance.

I always make sure I'm 1% rule or better, >7% CoC and positive cash flow with the 50% rule (generally I'm predicting ~40%, but in case I've missed something, I stay conservative). 

In the markets where they all 'agree', it's my opinion that those markets are likely fairly predictable to your expected rental activity. 

Predicting the stockmarket to pull back drastically, then the housing will adjust accordingly too.