1. ZZTJ, and each of their individual sgz's.
1 Where did you get the info that Zhuge and the others had different objectives?
2 How do you know ZL only received surrenders? I'm not sure if you meant that the others did the fighting while ZL would formally come and accept their surrenders or that everyone in ZL's way surrendered to him thus it was impossible for him to fight.
3 Why would it matter if Huang Zhong is in the van or not? Even if none of the big name generals were with ZL, ZL is never going to be personally fighting on the battlefield since he does not seem to be physically able. Thus if we apply this logic then all commanders who cannot be on the frontlines cannot ever be credited.
I think Huang Zhong was already with Liu Bei. It was Zhang Fei, Zhuge Liang & Zhao Yun that came with the reinforcements. Zl was with Zhao Yun for some of it before they separated and took different routes before they all met Liu Bei.
2. Any fighting that would have occured with the main body of troops would have been done by Huang Zhong, andnot Zhuge. We see this again with Ma Su, except that at that time, Zhuge was in charge of military affairs. I don't believe that Zhuge was made Grand Army Advisor (I forget the exact name) until after Hanzhong. Since Zhao Yun and Zhang Fei were sent out to fight those who were not surrendering, and since Huang Zhong led the van, one can summize that any fighting done would be done by them. I don't know if Huang did see combat during this or not.
3. I don't beleive that Zhuge had anything to do with the battles, other than leading the troops to Liu Bei, which is what it states in his bio. Zhuge had nothing to do with the military at this time, and had no experiance in the past.
4. Huang Zhong did follow Bei into Shu, but ZZTJ states that Huang was also with the main body as they moved through Yi, so I believe that he met with them near the beginning of the invasion.