The Transformers are a popular toyline by Takara and Hasbro, the spiritual predacessor of the Brave series.
Several of the Brave toys were recycled from the Transformers line.
The storyline of the Transformers cartoons and comic books features obvious paralells to early brave anime.
Ask Vector Prime would establish Brave is part of Transformers multiverse in the Megavwrse and that the Brave Mechas "shared body forms" with Cybertronians as a nod how Brave reuses Transformers designs. The events of Brave Exkaiser is cannon and part of the Transformers Multiverse and takes place in Cymond 290.03 Alpha.
Characters in Brave associated with Transformers
Brave Exkaiser:
Horn Geist- Based off of G1 Slag
Ptera Geist- Based off of G1 Swoop
Armor Geist- Based off of G1 Snarl
Thunder Geist- Based off of G1 Sludge
The Brave of the Sun Fighbird:
Fighbird and Granbird: the leg design of both characters has parallels with Star Saber from Transformers: Victory (this Transformers line set the standard for most of the Brave Series)
The Brave Fighter of Legend Da Barn:
Gaon- based loosely off of Victory Leo from Transformers: Victory in terms of alternate forms and concept
Red Geist- based off of Deszaras, also from Victory