I have baby gates set up to keep the dogs out of the cats room (they like to raid the litterbox and eat the cat food) and we have a gate set up to keep them in our room at night when we are sleeping- so they cannot countersurf (though they seem to have matured past that now).
Neither of them would keep a bunny out- as they do allow the cats to squeeze thru. But you could easly zip tie some NIC cubes to the gate and make the space impassable that way.
When the bunnies are out- to keep them from going upstairs or back downstairs (to tick off the other bunnies..hah, hah I am free and you are not) I just use the extra X-pen panels that we have from modifiying 2 x-pens to make 1 large divided pen with 2 doors. I have also used Coroplast and and NIC cube barrier. But now that Griffin gets over anything under 4 feet- I have to use the 4 ft xpen panels.
If you are using it for a free roam situation I would stay away from any gates that have plastic mesh screen as that would be a bored bunnys delight to chew thru that. Or modify it with NIC cubes or something else to prevent an escape.
Our baby gates are only about 2 1/2 to 3 feet high and our dogs will not jump them as they know they are not supposed to- (approx 50lb Aussies that could clear that easily). But my 9 lb rabbit is the trouble maker that needs a 4 foot pen with Coroplast clipped to the top to stop escapes. Figures. 