You've described the problem, but supplied no information to allow remote diagnosis. Without a schematic and related code, there's really no way to help, aside from the most general suggestions regarding jumpers, pins and I2C pullup resistors, all of which you've likely read (and hopefully applied). Finally, you mention migrating an existing project; did you have that working, and if so, under what version of Energia?
Re: UART - there may be no hardware UART on your chip.
"If your Launchpad is version 1.4 or earlier, the chips that it shipped with have no hardware UART and thus, no hardware configuration is necessary, but you must use the SoftwareSerial library included in Energia to communicate over the serial port."
You indicate you have an MSP430G2452, according to SLAU318G, there is only USI availble on that chip, the UART is on the G2553's USCI impementation.