I haven't kept tomatoes, but any frogs with that much of a size difference can have problems, especially with the tomato's big mouth. For example, if the tomato mistakes a chorus frog foot for a cricket, there could be trouble... Even just hopping around, a tomato could easily mash a chorus frog.

I've kept spring peepers, gray treefrogs, and bird-voiced treefrogs with chorus frogs. These guys may be more suitable if you really want a multi-species tank.