How can I gift money or territory to my ally.? 

The deplomacy screen was so elegant and well done in Endless Space / Legend. 

I dont understand why it was changed for humankind. 

I cant find plenty of options, on this new interface. 

There's no way to do that, because they went away with nation-level barter replacing it with negotiating contracts, which makes quite a bit of sense.

That being said, swapping money and territory has a historical precedence and hopefully we'll get an option for that at some point in the future.

To be honest that something we have in our mind for the future as it would clearly add nice way to interract

Have a nice day