1 - It could be that cIOSX rev19 just doesn't work with Hermes cIOS installer. It could also be that IOS 249 got damaged somehow. I recommend using IOS 36 to install cIOS 222.
2 - I tried looking up info about IOS 236 but couldn't find much usefull. Just try reinstalling cIOSX rev19.
3 - No, you do nit need to install a region changer. Just use the setting of your USB Loader to force NTSC video mode for PAL games.