Unreal engine C++ assistance and Steam multiplayer

My friend and I are looking for some help with regard to a project we have been working on for the past 5 months. My friend has been developing the game and I have done all the art so far (see attachments to get a general idea of the quality and style we are going for.

We need help on the developing front to get our demo up and running to pitch, the tasks we would need help with are:

Send/receive invites (through steam)
You can see yourself and others (in 3D, like Fortnite) in the lobby
Start match count down. If 66% or more of the team has pressed ready, the game countdown starts. The countdown is 7 seconds.
If being invited overlay popup shows.
Add the main objective to the map (3 components, spawn ‘‘random’’ (create x amount of possible locations)
UMG, simple interaction, 3d world space UI. This Is needed for the A) primary objective/components as well as the resources that can be collected throughout the map. Resources also need to be spawned randomly but more generous
Extraction point, if the players have all 3 components, they can finish the game, if not they need to search long before the TIMER runs out.
If the time is up there should be a huge zombie spawner making it so the player can maybe last an additional 30/45 seconds if they have good aim.
Add secondary objectives, and keep track of (examples):
Total kills; total headshots; Total melee kills; total, etc. This system should be very modular (use a data table).
Add additional animation states such as when looking up that the character looks up as well. (animations will be provided)
Add jumping to zombie AI. (Use nav link proxy).

we are just a bunch of friends who have been working together so our budget is not incredibly big but we are able to pay around 3 to 4k dollars. Let me know if there is something we can work out.

Kind regards,

Nathan