On the Broadcom side, we do not have anything in the form of a premade application that transitions you seamlessly from a wired MCU configuration to one that replaces the wire with Bluetooth.
The PUART is the one you would want to use as the HCI UART is for programming only.
The two PUART apps we provide in the SDK are uart_firmware_upgrade and puart_control.
JacobT_81 also put together some simple SW here which may be helpful: Connecting an external board to the BCM2073X via the PUART
If you need something with a less steep learning curve, you may want to look at the ACKme Bobcat (userc_6124) and Anaren (mida_2165396) development kits as they are much better suited to perform something like this off the shelf.
There are numerous threads related to changing Tx power and Pairing. Most of the pairing information you need is provided within the sample apps.