I am definitely with 9. 7. and 2.
Although I am not quite sure about the kind of things that should be linked from SP, at least somethings from there should be in MP.
As to specific places, well, for starters, I find the Blackwall as a good candidate. It will even provide a good background to MP modes in order to give them a purpose as the goal would be either to successfully breach or defend the wall. For instance, we could have a hack the node mode, similar to capture the flag, where both teams, attackers and defenders, are fighting over the control of these nodes. I believe this will provide a good balance between classes. Solos, from either teams, will provide cover fire to their fellow netrunners and techies to capture the nodes. As an extra challenge, netrunners would be capable to capture the nodes much faster than techies, but at the same time techies would not be interrupted when getting hit during the hack. Or maybe keep it purely relying on the fast reflexes of each player when executing hacking commands.
The Blackwall setting would also provide some sort of a periodical challenge that can be used to show, lets say each month, the percentage of successful defenses or breaches in the Blackwall. Maybe this could provide some bonuses to either attackers or defenders, similar to For Honor.
This is all based on the assumption that we are going to have the same classes. I hope this is the case, and I also wouldn't mind having extra classes.