We work with polyethylenimine - it usually will only protonate on 1/3 of the Nitrogens at normal pH values. If you have a basic N two carbons away from a much less basic O, the protonated on N form will drastically change the basicity of the O - the two + charges do not want to be so close together.
I had very good luck cleaving ethers (on a small scale) with BI3. It is nasty stuff and you need a glove box to keep it dry, but it will cleave those aryl ethers in high yield and very quickly. We would hit the aryl ethers with a little of that stuff, work up with water and get phenols in minutes.