@adsin - As I read through the history of your FLF, my guess is that the initial problem, prior to your repotting, was due to underwatering. You don't need a dowel to determine when to water. A properly potted and rootbound FLF needs a thorough watering as soon as the SURFACE of the soil feels dry to the touch. No dowel required!
The subsequent problems are a result of the repotting and the soil replacement, which is never a good idea. Your tree needed more frequent watering, not a larger pot or better soil. I don't know how it is potted now, so it is hard to advise you on proper watering. But as Ken indicated, the soil should stay moist, although that could be a problem if it is now in a much larger pot.
Thorough watering should not be a problem nor require a trip to the bathroom or moving the tree outside. Keep the pot in a sealed planter or have a saucer underneath it to catch any excess water. Water will run around the outside of the rootball only if the soil is allowed to get too dry and pull away from the insde of the pot. If that happens, let the pot sit in a couple on inches of water for an hour or so to rewet the soil. Avoid letting the soil get that dry in the future.
Fertilizer should not be used after repotting.
Be careful about moving it outside to a southern exposure when the weather warms. Outdoor sun is much more intense than the indoor sun and many of the leaves on yours will be acclimated to the reduced light indoors which is less intense than you realize.
Try to get the watering under control and hope that the roots gradually recover from the damage done during the repotting.
