He'll likely answer when he can as it seems his intent is to start the RP by the end of the week which means he plans on being around. Some do not have has much free time as others even then. He'll come on when he comes on. 

Even for your question on why our characters aren't Chimera rank, that one can be assumed to be due to the fact that it requires the actual completion of a hunt and killing of a paranormal creature as well as the presentation of a trophy to prove as such. A Hybrid beast may mean an actual paranormal creature rather than wild fauna larger in size than normal, which I imagine would be the norm for those who actually perform their duties as Swordseekers. So attaining the needed trophy isn't likely to be as simple and clear cut as the other ranks. While the first one is a test of physical strength and the second one a test of mental durability, the third one is a test of finding a true hybrid creature and killing it. Something that, if this is similar to the witcher, would be difficult to any normal person to ever do. 

Also, I don't consider the GMs character all that old. He is 32 to which makes plenty of sense. It likely took a long while for him to train to a level to complete the Minotaur rank and a bit of training to complete Sphinx. Unless he was trained to be a warrior or something similar from birth, I'd expect him to be between the ages of 25-35. He is human and doesn't have any physical advantage that an Elf or and Orc would have for either of the challenges. On the topic of why our characters were hired for the mission, I imagine it is also like the Witcher in the aspect that they aren't specifically hired for their missions. They are either assigned the mission or take the mission on themselves. Sort of like accepting a contract.

Now, mind you, this is all speculation but it is speculation that is of a reasonable nature and doesn't break any logical progression of realism. Simply answering questions as I can since it is in our best interest to at least talk about it and provide ideas while the GM is out for work. If he returns and states otherwise then it is fine but I imagine this is the quickest way to move along rather than hang on the fact that we have to wait for our GM who likely has a busy life working and attending to other aspects.