When I take of in 1st(low) it'll slip-n-spin too !
I wouldnt take anyones word that the trans is bad until you hav had it properly diagnosed by a trans specialist.
The fluid & filter could be changed to see if that helps.
You dont hav a distrubutor cap either
Ignition modul could be bad causing it to run poorly.
When you cleaned the IAC did you turn or push the tip that sticks into the TB?
If you did it could be the problem with idle, because thats what the Idle air control(IAC) does.
Sounds like you hav wasted money on stuff that could hav been tested first, that kinda sucks.
You can do a search on those coils and Ignition mod,
and thiers instructions I had posted earlier on how to test these on the 2.4 with a multimeter and a light probe.
And Welcome to AF !