fosc<2:0> is the first 3 bits of the configuration register, which is written during the programming of the device.
I have no experience with this model, but I think your setting of oscon (01110110) is correct if you configured the fosc<2:0> as "100" (see "Special Features of the CPU" section in datasheet).
Normally, for internal clock source, SCS must be 1. This bit allows you to switch between internal and external clock sources during runtime. But the datasheet states that when SCS = 0, the settings of fosc<2:0> is used, that's why I think SCS = 0 can be used for internal clock when fosc<2:0> is properly configured. Actualy, as you don't have a external OSC, I guess this is your only option.