First, Chinese inheritance has a national law. But in US, 50 states (and DC) have state laws. There is no US federal inheritance law. So you have to check with your local state law.
遗嘱可以剥夺某一合法继承人的权利吗?
Yes, but in some states in US, you cannot leave your spouse with nothing.
遗嘱可以跨国有效吗?
Yes, as long as the will satisifies local legal requirement, such as who witness it, who signs it etc. Local = chinese national law and US state law.
遗嘱跨国使用需要翻译公证吗?
You at least need a translation, whether notorized or not, depends on local law.
牵涉中美二国财产的遗嘱,需要同时满足二国法律吗?
Usually, US property needs a US will satisfies local state law, and Chinese property needs a Chinese will satisfying Chinese law.
如果回答是YES, 我的直觉遗嘱无用,除非只有美国的财产。
Will is very important.