replace old wood fence on top of emu wall

Hello , I am a home owner and we have a back wall that is 36" high CMU, with wood on top of that for a total of 6’ high. The wood is really old and looks to have been done by the previous owner, (bolted on top of the cmu caps. The property on our side is about 18" higher than on the neighbors side, so its retaining a small amount of dirt, but both properties are flat.

We would like to replace the wood paneling on top for a new horizontal wood top.
We live in California, Glendale area, could some one give us a feedback, as to this project which seems to us as fairly simple , we don’t want it turning into a horror, if the inspector will require engineering plans, property line survey, etc to replace the wood. (the companies that came out said they would install steel pipes with concrete inside the wall which the wood panels would attach to.

We called a few companies and the job itself was quoted to be a 2000$ but most of them told us that the inspectors might ask for a lot more before we get approval for the project…

a survey would cost us 2-3000 dollars, alone if we needed that!!!

could someone chime in with experience what is needed to complete a job like this,
Much appreciated.