Of course you can do flatland tricks on a TR5. I can do a number of basic tricks on my road bike. If your fork isn't equipped with 990 bosses (and it won't be) you have basically 3 options.

Good: Buy a Bulldog-style sidepull brake. This brake mounts through the little hole at the bottom of your steerer tube on the fork.

Better: Buy a 990 plate, which mounts through the same hole in the fork and adds 990 bosses to your fork. Now buy the front brake of your choice. It may be necessary to zip-tie or otherwise fasten the mounts to your fork legs (in addition to the mounting bolt) to keep the plate from walking on your fork.

Best: Buy a fork with 990 mounts welded on. Buy the front brake of your choice.

If you're running a gyro it's a good idea to run the front brake cable through the steerer tube on the fork. This will allow you to spin your bars without tangling your brake cable around the head tube. Check to see if the compression bolt on top of your stem has a hole in it for a brake cable. If it does, you're in business. If not, run it down to your LBS and see if you can replace it with one that has this feature. Sometimes you can, sometimes you can't, depending on the fork.