So, been doing some research as it's been awhile since I actually went thru and played SR series.
The reboot is actually, very possibly, Canon.
In the end of Gat Out of Hell, Gat is given a number or choices. Almost all of these are personal, except for one: one where the entire saints row timeline is reset.
The end of this shows gat and kinzie as cops interrogating a character from Agents of Mayhem. Meaning that it is the technically canon end.
This entirely leaves the door open for the New Saints to form in Santo Ilesso, while fitting into the story line.