Let’s say we pay X amount in mortgage.My question is : how do I calculate mortgage/interest/property tax for other house which we have rented so that I can deduct that from rental income?

Yes, they are. separate meters and property tax bills.  

We both work remotely and are curious about how long we can stay at the rental before it becomes an issue, wether thats state tax implications or perhaps when our jobs should be notified that were working in WA vs OR?

But between my broker fee and the lenders fees, it's usually 2-3% of the loan amount.They're ignoring the $7k escrow for taxes and insurance, for example.

If for example a home is selling for $225,000 it will have an estimate of $1,462/month.With 25% down the calculator shows: $1,023 per month Principal and interest $806Property taxes$125Homeowners insurance$92How can I get a better idea of the total including everything? 

Any tips?

Work with an experienced tax planner/strategist specializing in real estate and not merely a general tax preparer.

It would be same as saying you also owe future taxes and insurance.

Here are some of our top tips to help you get the most out of your investment:Market Understanding:-Research current local real estate conditions.

This means expect tax increases, expect HOI increases, expect tenant issues, PM issues, capex issues, everything in between.