集体户口上一页有许多名字,是否需要作什么标记指明我的名字给移民官看?
Don't worry, I think the visa officer knows Chinese. :)
Seal 是否盖在我的名字上?
It should be. But not very important, I think.
最后,是否可用这个证明办理出生公证等?
You may try it. If the notary doesnot agree, maybe still you have to try another way. The rule in China is no rule. :(