A worldwide council, quite possibly. This worldwide council, no. Most countries, particularly democratic ones, would refuse to sign up for this structure. It is at once too onerous (I assume point (3) is a typo for "supply a number of troops proportional to that nation's population", otherwise Luxembourg would have to supply an equal number of troops to that supplied by China) and too obviously toothless, assuming point (2) is taken seriously. Point (2) clashes with points (5), (6), (7) and (8).
All of the latter four are powers that define a sovereign government. For any government to surrender these powers is essentially to surrender its own existence. They might be willing to do that in the hope of being able to deal with some desperate crisis but they are most unlikely to do it in exchange for a predictable state of permanent indecision, which is what you will have if point (2) is taken seriously. A requirement for a two-thirds majority for every decision ensures there will be very few decisions made*. Additionally, if "majority" means a majority of national delegates it gives disproportionate power to smaller nations. Using the same examples as before, China isn't going to take kindly to having the same number of votes as Luxembourg. If, however, "majority" means majority by population the voices of smaller countries will be utterly drowned out.
The only way I could see the first interpretation of point (2) happening was that if the inability to come to decisions were regarded as a feature not a bug. As I said elsewhere, there might be times when the ability to draw out the decision-making process indefinitely is very useful, particularly since a feature of your scenario is that Earth has been thrown into a vastly wider society it knows nothing about. Smile nicely at everyone and delay while we find out what will and what will not get us all killed.
Putting that discussion aside, the most likely model for a world council to be structured in a way acceptable to most countries' governments is the one nearly all of them already have agreed to, the United Nations. The Security Council with its reduced "cabinet" of the most powerful nations, dominated by the five permanent members, is not particularly fair, democratic, or even effective, but it does avoid paralysis.
*Apart from the immediate and unanimous vote that all Council delegates need a $1M tax-free expense account.