Also the fact that they don't want to use Vitalik as promotion channel should be brought into question (as far as marketing is concerned).
Regarding to the Cooperation-Questions as mentioned see:
See the questions in the AMA:
https://app2.sli.do/event/xbsrzmm1/ask?utm_content=buffer1fdfa&utm_medium=social&utm_source=twitter.com&utm_campaign=buffer)
See the answers in the latest AMA:
https://www.reddit.com/r/WeTrustPlatform/comments/7amka9/wetrust_ama_5_november_3_recap/
Vitalik is like the trump card, you can only play it once. He is a advisor to over 5 cryptocurrencies from what i hear and certainly can't go promoting each and every currency. He is more from a technical advisory point of view and yes his statements do hold value but if he openly declares support for one currency and if it doesn't deliver, the other teams advised by vitalik stand to lose from it. The only point which bugs me about wetrust is the low percentage of coins they have kept for themselves. Only 8 million of a pool of 100 million which really puts them at a spot that they don't stand to make good profit for themselves by these gains. They really have to shoot for the stars to accrue something for them. I have found a 60:40 to be the best means to raise money and give the developers and the team a chance to really work for in order to earn millions for themselves.