The knee bone is connected to the...

That's an old song but the idea is well worth thinking about. Here are a few examples:

  1. The Electrical issues (these are always #1) - Everything else can wait but sub-standard wiring is unsafe and I like to keep my clients safe! So I want to have the defects in this system corrected/repaired and as long at that is being done I want the licensed electrical contractor to plan for future needs. For example: if the basement bathroom is going to be in the room with the existing electrical panel then the panel will have to be moved to a different part of the home. And if the area that contains the existing chimney is going to be finished in order complete the unit in the basement then this would be an ideal time to run some electrical conduits or wires to the area of the new master suite. (Conduit is cheap, undoing finished walls costs $$$.)
  2. Lining the existing masonry chimney will cost several thousand dollars. For about the same cost, it should be possible to install a new high efficiency furnace that vents to the side of the house and also install a similarly vented water heater.
  3. The reason that the fireplace never did work well had to do with the fact that it was designed to use coal. It is too small for wood. It might be possible to insert a small gas fireplace into the existing fireplace at a cost well bellow that of re-building the existing unit into a wood burning one. The gas unit can use a thin metal flue and does not require the existing chimney.
  4. Now that the old chimney and its two flues are no longer used for the fireplace, furnace and water heater, It would be possible to get rid of part or all of the old masonry structure. This could free up some potentially valuable space on all levels of the home.

  5. Similar space might be made available if the old asbestos covered ducts are replaced with new ducts. And if some of the duct system can't be modified at a reasonable cost, it might make sense to heat part or all of the home with dual-purpose water heater and radiant heat...

Well, you get the idea, its all interrelated.