The correct way to get a radical engine to idle is to adjust the IAC bypass like BB said, and with tuning.  Only a hack would drill a hole in a throttle blade in an EFI application.  But its a BBK TB, so it'll probably start leaking around the shaft fairly soon anyway.  When it does don't buy anything other than an Accufab.  Best TBs made. 

Would IAC be removed with home-brew design?

How would ECM react to its removal?
Could it be located elsewhere to cleanup engine compartment?

Have to admit, design and placement of IAC and EGR could have been done better.
Hot Rod ideas swirling around with the snow in my head, eyes, and ears.

Just trying to understand “what if”

Its the same thing some guys would do by cracking the throttle blade a tiny bit on setups that were adjustable.  The problem is that you are again trying to trick the ECM, when its better that the ECM knows whats going on so it can run the engine properly.  You can adjust the idle RPM and the IAC steps in the programming to get a radical cam to idle more smoothly and not have to worry about it stalling.  Over the years guys came up with all kinds of work arounds to avoid ECM tuning, but ECM tuning is and always was the best way to get the engine to do what you want.  All the work arounds involve trickery.  The system works best when you aren't tricking it.  Years ago the only way to tune was to go to a tuner, which were few and far between.  Today with the right setup anyone can tune the EECIV.  There are voluminous online resources to help, and many of us have tuning experience too. 

You can't remove the IAC.  The IAC exists to maintain an idle under all circumstances.  When the AC comes on for example the IAC steps up to make sure the engine doesn't stall.  It does the same thing when you push in the clutch and coast to a stop.  Anytime there's a load placed on the engine and it has to idle, or the throttle slams shut unexpectedly; that's when the IAC has to do its thing.