I have some questions on the Zaydiyya

wa alaykum as salaam wa rahmatullahi wa barakatuhu!

Thank you for your questions!

1. You can find a reply to this question here
2. As for the Musnad Zayd, we do not say that Imam Zayd (as) wrote it. Rather, we say that the narrations and reports are attributed to him through his student, Abu Khaalid al-Waasiti. 
3. I wouldn't consider the following Sunni beliefs as 'heretical'; rather, I would say 'problematic': The belief in the Vision of Allah in the hereafter, eternality of the Qur'an, the exiting of disobedient Muslims from the Hellfire. Our past imams considered the belief in Predestination (in that Allah created the actions of the slaves) and the tendency towards anthropomorphism as heretical. 
4. Zaydis hold to the Guardianship of Imam 'Ali (as) as proven by the Qur'an, authentic Sunnah and logic. You can refer here for a brief proof. As for how we would convince Sunnis, we have actually written a book dedicated to this topic as well as others. The book utilises Sunni sources in addition to logic. I would start there.
5. Zaydis hold the ritualistic mourning customs related to Ashura as being innovations. Of course, there is no problem in commemorating the martyrdom of Imam al-Hussein (as) or anyone else if it is a means to encouraging a religious principle. However, the customs such as the ritualistic beating, wearing of black and wailing are explicitly condemned in our books. 
6. Zaydis hold to the Sunnah of praying with the arms by the sides and reject the practice of folding them or crossing them. You can refer here for questions related to the prayer. One of the questions was related to crossing of the arms. We've also written an article that addresses this topic.  
7. One need only to study Zaydi usuul to discover the source of Zaydi doctrine. The precedence given to the consensus of Ahl al-Bayt doesn't sound Sunni or Twelver. Such doctrine does not form a fundamental in Sunni or Imami usuul. Therefore, any similarities one finds in theological or jurisprudential principles are just that--similarities. 
8. Zaydis see anything beyond the imamate of Ahl al-Bayt (as) as illegitimate. Any state or empire established without the imam from Ahl al-Bayt who is obligatory to obey, is seen as a violation of Allah's injunctions. 
9. Many English websites have come and gone; some still remain. You can refer to Youtube pages such as this one , this one , and this one   You are also welcome to peruse the salvationark.com website. 
10.  I don't know of any opinions regarding Abu Lu'lu.

And Allah knows best!

IRS    

I didn't know that about the channel. Thanks for sharing!

I never came across anything about the permission of beating the chest. At the same time, most of our foundational texts omit the mention of beating the chest. 

As far as I know, there is no explicit prohibition of cursing them; however, it is contrary to the practice of our imams (as). 

As for calling upon the imams (as), this is impermissible if one intends by such the belief that the imam can assist. However, if one calls Ya 'Ali intending Allah, since this is one of Allah's Names, this is permissible. 

And Allah knows best!

IRS