From memory you don't have to place all of your fortifications. However I don't seem to be able to find a rule reference.
I've been leaving some off as they do provide some benefit to the Chinese in the 2nd and 3rd scenarios. Conversely in the last scenario they provide cover for the ridelge runners.
In terms of MF I've been playing them as FHs.
Have fun, great scenarios.
Thanks to Klas for answering the 'do I need to setup all the fortifications' question
Q&A:
A2.9
Must a player setup all units/concealment/fortifications in his scenario given OB? If Yes, does a player who accidentally leaves off part of his OB immediately forfeit the scenario? If No, are units not setup considered eliminated for CVP? Immediately or at scenario end? Should double CVP for capture be assumed, if allowed by the scenario VC? Would any fortifications not setup which count for VC be considered captured by the other side?
A. No. No. Yes, they would be considered eliminated or captured at option of other player. Immediately. At the option of the other player. Use whatever is most beneficial to the other player when considering non-setup Fortifications, either eliminated or captured.
Must a player set up all units, fortifications and other counters listed in his OB? Do the units not set up count as eliminated for CVP purposes? Do fortifications or counters not set up count as captured/controlled by the opposing side for VC purposes? Must a
player inform his opponent of the elimination/capture/control of said units/fortifications/counters when the elimination occurs?
A. No. Eliminated, captured, or controlled at other player’s option. Yes. As soon as it might be material to the VC.
Must a player enter all units and counters (ex: motorcycles/horses) scheduled to enter as reinforcements (assuming no SSR mandating entry as Riders/Cavalry/Mounted, etc.)? Do the units not entered count as eliminated for CVP purposes? Do counters (e.g. motorcycles/bicycles/skis/horses) not entered count as eliminated/captured /controlled by the opposing side for VC purposes?
A. No. Eliminated, captured, or controlled at other player’s option. Yes.