Number one, if your gonna ask for advice, please don't ignore it. Number two, your tank is allready way overstocked. Both your pleco and your bullhead do not belong in a 17 gallon tank. At a bare minimum, for the stock you are planning, a 180 long will be better, but will not be the last tank you will need. Also, everything you listed will be eaten by the bullhead, except for the pleco. They can fit fish almost as big as themselves into their cavernous mouths.
Please do not get a channel. They can get to be three feet long, and are alot of fish. Also, please do not release any fish into a naturalized pond. If you have a garden pond, feel free, but any naturalized body of water has the possibility of allowing diseases and non native fish escaping. This has many dire consequences, from disease transmission that could wipe out a native fish population to agressive non natives being introduced that could also wipe out a native fish population. The fish you release may be fine, but what about the other fish? This kind of attitude is what results in legislation like the one we recently faced, the ban on importation and sale of almost all of our aquarium fish.
Is that what you want to be responsible for?
On this website, we try to expouse responsible fishkeeping. Be prepared to be flamed if you ignore that, and ignore advice when given it. We all love our fish, and do not want to see someone treat them badly.