Usually townhouses have issues with vertical signal because the antennas are optimized as a disc. If you have horizontal issues, then moving the router more central may help (if possible). And yes, usually hallways are good for repeaters as they are usually central. I'm not really following your layout though. Do you have plaster and lathe walls or any metal? They are pretty bad for signal penetration.

The thing people miss with wifi extenders and mesh systems is you want them to have strong signal to each other - NOT positioned in the rooms you want signal in (because they will still have bad signal there). Ideally you want the extender/mesh point halfway between the source/router and the location you want to improve the signal.

In a townhouse, you want them aligned vertically with as little metal, glass, and plaster between them as possible.