Each element has an accept and reject. Should it have one accept
at the end for the whole filter?
All terms in a multi term list are processed in order. Thus if you have an accept or reject all term processing of that filter will stop at that point. So these final accept or reject all terms are used only once and in the very last term position only.
Will dropping the ipv6 traffic kill my connection?
That would depend on the necessity of ipv6 for any particular use or application.
But it seems like you are trying to apply ipv6 terms in an ipv4 filter. Remember that you configure both interfaces and firewall filters with a family hierarchy. So ipv4 interfaces and filters are set at family inet and ipv6 filters and interfaces are configured under family inet6.