What would lead you to believe that digital will be allowed on GMRS when they rewrite the rules? Not a flame, just curious.
The radio would not be legal to use under FRS rules because it has a removable antenna, and the power output can be increased by the user. Both of these items would make it fail under FRS rules.
Under GMRS rules, it would be legal IF it has Part 95 certification. I'm not going to guess if it does or does not. The only way to know for sure is to run the FCC id number through the OET page and see what the grant says.
IF it was legal under GMRS rules via type certification, then you could run the radio on one of the 7 interstitial frequencies that is shared with FRS. You would need to stay under 5 watts (not a problem), but you would still need to follow the letter of the law if you wanted to stay legal.
Part 95 rules, specifically the part of it that covers GMRS, spells out what emission designators are legal. If the emission designator used by the Trbo radio to send the messages is included, then you might be OK.
Using Garmin as a reference doesn't really apply because they have a waiver to do this. The waiver only applies to those radios made by Garmin. They do use GMRS to send them, but still, you don't have a waiver, and Motorola doesn't have a waiver, so this would be a dead end, if you wanted to follow the rules.
What would be easier, legal and a lot more appropriate would be to do this on the 70cm amateur radio band. There this would be legal.
I think the answer to your question is no. I know others will argue the point, we've all been through this before on other sites. Everyone has their own opinion and many have chosen to develop their own personal views on how to interpret the GMRS rules.
The choice is up to you.
Honestly, if I was going to do this, I wouldn't choose MotoTrbo. The radios are more expensive and the software is expensive. If you went with either Icom or Kenwood NXDN, you can do the same stuff on a less expensive radio and program it with less expensive software. I own several Motorola radios. One of the reasons I do is because I have all the programming software, cables and RIB in my shop at work. If it wasn't for that, I wouldn't invest in them. After programming well over 300 Kenwood radios recently, I'd suggest you look at their product for a much more friendly software experience, and a radio that is easily as rugged and well built and the Motorola's.