Fighting fish are like many fish these days. They come in all different shapes and sizes, depending on the shape and/or size they can be very different. A plakat should have a better chance than a fancy in a more aggressive tank. The more you line/inbreed fish the more weak they tend to be. Again, it all depends on the individual fish, each seem to have their own personalities so you should be able to see if they can hold their own or not.
HTH