well you hear the whirring sound from the pump kicking on and your sure the starter is enagible still because the swap and the starter is good then i guess check for power along the wires to the starter into you find a loose connection or somthin, you got a gauge to test them?
I guess you can do this, but make sure its safe first! just run a positive and a ground to your starter while its in neutal and if it starts that way just throw a push button starter in, that would be cheap, easy, and the first time a push button starter is used for a good reason.
Ive though about doing some thing along the lines of this for my legend since somtimes i park in some bad areas down town. It would be cool to run a relay switch between your key ignition power wire through a relay switch, so you could make a break in the wire if you were parking in a bad area or somthing, or either make it run from a sensor or coil, or anything that will make your car not start to make it even harder to steal. just run the switch under your seat or somewhere not obvious.
if they are a pro they might be able to get past your alarm, but i doubt they would take the time to figure out whats keeping it from starting after they try the usual things. but anyway, i doubt a professional would take a g1 legend lol.
If you really twisted you could run a switch to turn power on and off from your ignition coil into the gas tank and blow everything up lol. you my accidently kill yourself doing that one though