I would say all of those are good issues. You should introduce all of them into the conversation-- eventually. I have found that, when dealing with my JW family, it is better to casually bring up one point at a time. Many times I have started a conversation over something that I read on this forum and asked them what they thought about it. It seemed to open dialogue and they didn't feel as if they were being cornered or attacked. Over the years this has paid off.
Is it the blood issue, either based on a scriptural attack or else a humanistic "value-of-life" approach?
Does the modern-day history of the organisation, the lies and changes and evidence of false prophecy provide the best opening?
Or are the scandals and lies, like the UN scandal, or the owning of shares in military companies, the biggest chink in a JW's suit-of-armour?
Here is the order of what affected my family the most:
First the blood issue.
In private, my family has never really believed in this doctrine. I have found many interesting threads here on this subject. Some of the info I found helped get them over any remaining hurdles they had in disregarding the teaching.
Second: The lies and Scandals.
The UN scandal and the pedophile reports literally made them sick. Especially when they saw the Dateline episode a couple of years ago.
Finally:
The False prophecy of the WTS. Also the demands of the WTS that it's publisher's spread those false prophecies from door to door.
No matter how the JWs respond when they hear about the above, if you just act curious and do not be confrontational, they will not feel the need to defend their beliefs. They WILL think about what you have said. Even though they think about it, it can still take years before they decide to act on it-- so do not become discouraged.
Good luck,
Robyn