Moving from bluetooth module to chip
There is a plethora of pre-fcc-certified BLE modules that have come out over the past 5 years or so. The RFDuino uses the nrf51822 (as most due to my amazement considering the terribly black box nature of that SOC), as well as the uBlox NINA-B112. Murata makes a really tiny module that is also precertified that makes use of the Dialog Chipset, this Atmel SOC and this Alps SOC (F****** tiny). Best to find the one that best fits your project size and cost goals. Generally speaking, if you can find example firmware from these manufacturers that provides some sort of pass through via a serial bus you should be along pretty quick. Look through the datasheet for mentions of "UART application" or "SPI Slave Operation" or something to that effect and you might find exactly what you need. These modules usually just need clean power, good decoupling and a few pull ups and you are in firmware land.