First, is "Major General" a federal office in Atlasia? If so, what authority has made it a federal office?
No it is not a federal office. I was asked by the President to oversee military operations within New Mexico do to the fact that the President admitted that he has a limited knowledge of military affairs. Then in order to have any authority over the military I would have to be a comissioned officer so I was comissioned into the Atlasian Army as a Major General at the behest of the Commander-In-Chief. The only way I could construe that this is a federal office is that I was asked and given the job by the President however when the President, say, appoints advisors in other matters, like the Council on Economics, President's have appointed people who were not citizens or were also members of other governmental entities. I see this position as no more than the other special appointed positions that President's sometimes create. Saying that a sitting Senator cannot perform these duties would also mean that no governmental officer could ever be appointed as Presidential advisers or to any other position created by the President and appointed by him.
The only place in the constitution that mentions an armed force or a military is in the powers of the Senate stating that they can raise an armed force and regulate it. Now you could state that these regulations can come from American law however I think Army regulations, which number in the thousands, which are well needed in the real-world have absolutely no bearing upon the military of a fictitious and completely internet based state. The dynamics are different and as such I think any prior regulations upon the military should not be directly admissable.
It would be within the Senate's power to create such a position through its ability to regulate the armed forces however the President, as Commander-In-Chief, can just as easily ask a citizen such as myself to be comissioned as an officer in order to take over the role directly. I'm sure the President would have taken over direct control of the situation if he was more versed in military affairs. As he is not and has never claimed to be he asked me to take over as his commander for affairs in New Mexico.
I believe that this is the same sort of thing. If prior officers, including Preston Caldwell several times including now, can act as military officers and give themselves or be given ranks within the Armed Forces of Atlasia than I do not consider what was bestowed upon me anything different.
Overall this is not an office of Government, it is never once stated in the Constitution, nor is the precedent completely clear. It seems to me that this position would be outside of the governmental sphere as it is a military position and seperate from any government duties. Just as a newspaper publisher or a GM are technically outside of the government. While we do have regulations concerning the GM and how the GM is appointed and who may be appointed no such regulations exist, as per the Senate's power to regulate the military, for bestowing army ranks and commands onto people currently in government offices.