From my understanding of the USAID appropriation, the majority of it is discretionary for the Executive Branch to award to specific programs. In that case, it is completely within bucket #1 of the executive's authority to not allocate that money.
Even if that money was explicitly appropriated by Congress for USAID to make a transgender comic book in Peru, it is not illegal for the executive agencies to under execute the budget, and in the year of execution, they can go to Congress (either for notification or permission depending on the specific appropriation execution scheme Congress has with that agency).
For example, if the DOD is developing a new sniper rifle and they have budgeted $100M in Research, Development, Testing, and Evaluation money for it, and they realize that they are able to gain efficiency and only spend $80M of that money appropriated, they are able to notify congress on the movement of that money into another program if they desire. Congress generally uses the actual obligated money data to "mark" a program, or remove money in the next year's budget, as an example. My experience with PPBE is entirely in the DOD though so I'm not really sure what exact scheme Congress has for the State Department, but I would wager it's pretty similar.
On buckets 1 and 2 I think it is a complete judicial overreach for the injunctions that federal courts have been placing on the executive branch that is an affront to separation of powers and SCOTUS needs to rule on it swiftly. The liberal judges are being incredibly short sighted and going to ultimately result in an opinion leading to a very strong unitary executive.
Bucket 3 is completely fine for an injunction IMO. I am of the Originalist Public Meaning opinion that the 14th amendment was never meant to provide citizenship to non-permanent residents of the country, which inexplicably includes illegal immigrants. However the textualist argument certainly would be in favor of birthright citizenship for illegal immigrants. Would be a monumental case.