I modded an ocelot to be rideable by the player, much the way a pig is rideable. There is a Speed boost attribute to this riding feature. For other animals i can modify how fast the animal moves, however no matter what i enter for the ocelot, it does not change the speed. So, the result is a very slow moving ocelot while you ride it.....which is not exactly why you would want to ride an ocelot.

Below is the code i am using within the Ocelot JSON

"minecraft:rideable":{
"seat_count": 1,
"interact_text": "action.interact.ride.horse",
"seats":

{ "position": [0.0,0.35,0.0] }

},

"minecraft:boostable":{
"speed_multiplier":1.3,
"duration":5.0,
"boost_items": [

{ "item": "wooden_hoe", "item_damage": 5 }

]
},

the speed_multiplier appears to have no affect on the ocelot speed when i ride it though.