Favored Souls get Basic + 2 weapon groups plus the weapon group for their deity's favored weapon. In the case of Mayaheine, you get Weapon Group (Exotic Weapons: Heavy Blades) as your bonus weapon group. In this case you bypass the normal prerequisites for Weapon Group (Exotic Weapons).
If you want a flaw from UA, I will have to approve it on case-by-case basis in order to make sure it is actually a flaw and not something that you selected because it will probably never come into play or never affect your character negatively.
Those are fine. You can take up to two if you wish. Pick whatever feats you want.The options I would consider would be... Frail, Unreactive and/or Vulnerable.
You can research a new magic item by spending 10% of the expected market value of the item in research costs. The resulting item may be cheaper than expected (but no refunds for research cost), the same value as expected, more expensive than expected (requiring additional research at another 10% of the new, greater value) or the item may be impossible to make (IOW not something I will allow into the game). If you are willing to pay the research costs for crafting such an item first, I will let you know the results of your research. Research requires no XP costs, just gp. We will assume the research has taken place prior to the campaign's beginning of course.
Also, pointing out a similar magic item might help make my decision easier.
Contacts, page 179: For this variant, determine how many contacts you have and then indicate to me what kind of contacts you would like (arcane, divine, mercenary company, arms dealer, guild, etc.). I will then provide you with a description of each contact, as well as where they are located. If you know of a particular organization within the World of Greyhawk with which you would like to have a contact, you may request it specifically (although I cannot guarantee I will honor the request; it depends on the group, your character's alignment, etc.).