The 15L and 8L don’t have live tooling, a Y axis, a C axis, or spindle locking. One could certainly build a DIY live tool station but it would be effectively a drilling station only, you wouldn’t be able to mill an actual pocket. Even then, without a C axis and a spindle brake, it would be a dangerous thing to do.
Without knowing the actual geometry of the pocket it’s hard to recommend the right path forward but based on what you’re describing, a Tormach lathe alone isn’t going to do the job for you. A lathe with Y and C axis, and live tooling is the one machine solution but it will be costly. The alternative would be a lathe to do the turning work, and a mill (potentially with a 4th axis) for the pocketing.
As for Fusion, I’ve done little in the turning space with it so I can’t say for sure, but I believe it is capable of driving multi-axis lathes should you go that route.