4. Do I need to initialize the date/time variable in some way before trying to use the Goal 2 command?
As long as you have the "Evaluate 'Not Set' as 1/1/0001" option enabled (checked) within the condition, which you do, no.
Logically, 0001-01-01 is always before the current date (I.E. it is very much in the past).
If the intent is to be able to activate individual abilities manually as well, what you could do is to check for the cooldown within each individual ability command (I.E. have it check for its own cooldown), and then have the command that activates all of the abilities one-by-one just contain "Execute Another Command" actions.
The latter command wouldn't need to check the cooldowns, as that would already be happening inside the individual commands anyway.
Otherwise, you'll need to clarify what "doesn't seems to be working as intended".
You have the individual ability commands set up correctly, assuming you only want to trigger them using the command that triggers them all in sequence.
All you should need to do is to duplicate the condition you already have for the other abilities (making sure to change the variable names, of course).
If you want TTS feedback, you can add a "Condition Else" action to them as well, and a "Say Something with Text-To-Speech" in each branch.