Which branch of Tiger style? There are plenty.When I was a student of Tiger Kung Fu, back in the 1980s, sifu taught us the guard, the mount, escapes from the guard, ground and pound, high branches, low branches, rear naked chokes, wing chokes, triangle chokes, arm bars, wrist locks, elbow locks, chin na, gi chokes, and the list goes on and on. Were these things stressed to the same extent as a system which is primarily a grappling system? Of course not. Kung Fu systems are are primarily stand up systems. But ground techniques were taught.
Nonetheless, simply because it is taught by an instructor, does not mean it is part of kung fu. Plenty of people teach "ground techniques" in their systems nowadays, with these ground techniques coming from BJJ, Wrestling, etc. - That doesn't make them kung fu.
The fact of the matter is, there is not a single kung fu style that encompasses a comparable level of knowledge and effectiveness of ground game, that BJJ or Wrestling does. The only thing that comes close is shuai chiao.
Aside from that, "Everything in MMA is found in Kung Fu.", is such a ridiculous statement if only for the fact that MMA is a concept, not a style or collection of styles. Not only that, but is also ever-evolving, with the latest training methods which are developed based on the latest, and most up to date knowledge of the human body.
Thats not to say there isn't tons to derive from kung fu. Theres much that is relevant. But the MMA community is far different, far more scrutinizing, far more focused on combat and science, and thus you will find plenty in MMA that is not in kung fu.