回复：总结我和小白兔的分歧: 劳工卡I140及党员移民(合集)

You are correct on 1. USCIS can denied I-140 based on the lack of ability to pay the proffered wage..

Not correct on 2. There are CCP party members check yes and get aproval (of course you need to attach a page of explanation, i.e. your part history if you check yes, and may be interviewed by FBI) approval of CCP is absolutely not just single rare cases. It's like arrest history, many do get GC approved with arrest history.
Also true that if you are just a rank and file small patatoes member, it's usually low risk to check no to spare immediate troubles, because US is not interested to find you out unless you do something later. However, you leave something that US can use to strip your US citizenship when they want to get you.