drywall patch over block wall??

I have a one story home with an interior wall of my living room measuring 8ft high by 10.5ft wide. This wall does not connect to any outer walls. The other side of the wall is a large bedroom closet. I believe this wall to be a load bearing wall because the down slope of the vaulted ceiling in this room ends at this wall. This wall has 10 studs in it. The center stud and two outer studs consist of 2 studs side by side. I'm told this is for the load bearing purposes. Then there are two single studs spaced 14-16 inches apart on each side of the center studs between the outer studs. What I want to do is cut a 1ft section out of the single stud to the left of the center studs and a 1ft section out of the single stud to the right of the center studs. I then want to install a cubby/shelf into this space (one on each side of the center studs). My question is: Is this safe to do without my house falling apart?

I'm tackling framing for the 1st time...in my basement. What would be the best way to go about doing this..should I build the wall & toenail it into the joists above or should I lay a footer & nail the studs into the footer & the joists above? Any help would be appreciated..thanks.