I have this thought which is not what it seems, but an educational place for earth's humans and government to ask questions and learn about the "rules of engagement".
I think Mass Landings is a bad idea because it would cause panic and prone to negative media propaganda unless the ETs would seize control of our media channels a broadcast a long greeting and their intentions before showing up. Which we would take as a hostile sign...
Using a physical "embassy" it would be very controlled where governments and community groups can address Q&A and be educated about why they are here, if it is not to help us. Which I strongly believe.
The UN should designate a piece of land in Geneva somewhere where the ETs will beam their buildings etc and be there physically and meta-physically. They do not need to show their ships which can still remain cloaked. But they can be protected from any harm-inflicting beams/rockets/missiles etc. They can schedule meetings with humans all the time to answer any questions. And state the rules of communications.
This would be the most neutral way of easing humans into Post-Contact activities.
PS: If the Galactic Federation does this, the Illuminati will freak out first!.