So you are saying that you've got a complete top shifting 23-spline 2.28 case sitting on the ground right now?

If that is true then save yourself some time and just keep the 4.7s in the front case. You've already gone through the trouble of putting a 23-spline 2.28 input in a non-Turbo t/case, and that is just want you need to do if you were to go with Option Two above.

Then you would just tear off the 4WD stuff from the 4.7 t/case and then build the Crawl Box from that, and then just bolt your 23-spline 2.28 topshift case right behind the 4.7 Crawl Box. It's a direct bolt on, assuming you build a 23-spline Dual Case (with a 23-spline coupler).

Otherwise, you would need to convert your 4.7 case to a top shift, and then tear down that 23-spline 2.28 case and convert it to a forward shift and also build a Crawl Box outta those parts.