glad to hear you're doing so well! we have lots of post-surgery members who are very into fitness, though many don't post any more. if you look up some of GloomCookie's posts perhaps, there may be some advice, as she's a bit of a fitness fanatic. i'd suggest finding a personal trainer who you can explain your physiological differences to and ask them to help you come up with some exercises which allow you to achieve what you want but will also minimise future damage to your spine - scoliosis or not, everyone should be careful bending and lifting, so it's important to maintain the discs below your fusion. keep in mind that there's more than one way to skin a cat, so you may ask for abdominal exercises but come up with a plan that doesn't involve sit ups
you don't need to shell out for endless sessions - a good PT will be able to listen to your comments and know their stuff regarding anatomy. if anything's uncomfortable, find another way. and if you feel like exercises are no longer benefiting you and you need more difficult stuff, go back to the PT and ask for more!
best of luck