Would this be possible without violating FCC guidelines?
I'm going to offer this up as reinforcement to what was said above. Here's the specific rules for FRS/GMRS as they apply to your radio:
§95.561 FRS transmitter certification.
(a) Each FRS unit (a transmitter that operates or is intended to operate in the FRS) must be certficated for use in the FRS in accordance with this subpart and subpart J of part 2 of this chapter.
This means you cannot use a radio on FRS unless it has type certification from the FCC for Part 95. If your radio does not have type certification for Part 95, then it cannot be used under the FRS rules.
§95.587 FRS additional requirements.
Each FRS transmitter type must be designed to meet the following additional requirements.
(a) Transmit frequency capability. FRS transmitter types must not be capable of transmitting on any frequency or channel other than those listed in §95.563.
(b) Antenna. The antenna of each FRS transmitter type must meet the following requirements.
(1) The antenna must be a non-removable integral part of the FRS transmitter type.
This means that for a radio to be type accepted under FRS, it must not be capable of transmitting on any other channels. It also says that the radio must have a non-removable antenna. Since your radio can be programmed for other channels, and has a removable antenna, it would cannot be used under these rules.
§95.1761 GMRS transmitter certification.
(a) Each GMRS transmitter (a transmitter that operates or is intended to operate in the GMRS) must be certified in accordance with this subpart and part 2 of this chapter.
...
(c) No GMRS transmitter will be certified for use in the GMRS if it is equipped with a frequency capability not listed in §95.1763, unless such transmitter is also certified for use in another radio service for which the frequency is authorized and for which certification is also required. No GMRS transmitter will be certified for use in the GMRS if it is equipped with the capabilities to operate in services that do not require equipment certification, such as the Amateur Radio Service. All frequency determining circuitry (including crystals) and programming controls in each GMRS transmitter must be internal to the transmitter and must not be accessible from the exterior of the transmitter operating panel or from the exterior of the transmitter enclosure.
This means that the radio to be used under GMRS rules must have type certification for GMRS. Paragraph C says that the radio cannot be certified if it's programmable from the exterior of the radio. This would mean that being able to program the radio from the front panel would exclude it from being allowed under Part 95. BaoFeng usually locks out the front panel programming on these radios from the factory to meet this requirement.
NONE of us here are the "radio police". What you choose to do or not do is your own business. We are simply answering your question:
Would this be possible without violating FCC guidelines?
You can read these rules for yourself here:
eCFR — Code of Federal Regulations
Again, it's your choice.