Original loans were for 10 years - I would also like to extend the length of the loan to lower payments.  

If you have 250k of cash, they'll extend you a credit line instantly.

I know that some over extend and that's something to be cautious of, but I would do it conservatively.

Some lenders have what's called an "overlay" and extend that seasoning period to 12 months or even longer.  

Another lawyer to fix a problem with this landlord isn't going to get you anywhere,, the only other option is to pay your rent to the court it is put in escrow, send owner notice to fix the problem, take photo's and call city for inspection of area of home that's not inhabitable, so basically the landlord can't kick you out as long as your rent is paid on time to court, he can get the rent once the problem is corrected from the court but then he and you still have to deal with living together yet apart and he's not going to extend an olive branch if he can cut the tree down and give you proper notice to vacate..MOVE now when you know what's up and good riddance to the problems

While living here ourselves, we want our children to have good schools to attend as well as future tenants.Is there anything that we should be looking for as far as running the numbers when considering to purchase a property we plan on living in for an extended period of time before purchasing the next one?

Keep in mind the litigation period of one year that is extended to the previous property owners to contest in court the sale. 

I like to have interest only notes for 14 months with an option to extend for 6 months with either a bump in the rate or a point fee.

It has been our experience that most lenders will extend a secured line of credit to between 70% and 80% of the value of a residential property.

And once you get a reputation of doing 'good deals', assuming you keep the banking relationship 'clean' and productive, the banks will extend you the benefit of the doubt.