Ill do my best to help you out on your questions
1) with the IGR im not sure whether its controled by your bios or dash2gam which xbe it boots on IGR. but if it is dash2gam that determines it you should check the 1st line of your config pro file
ie
1='Dash2Gam' (where dash2gam is the name of the dashboard xbe)
2) to launch an an app (or in your case a dash from the main menu you need to edit your config pro to something like this
[ConfigMenusMainMenu]
...
9=M$dash
10=C:\xboxdash.xbe\
3) Dash2gam uses a static IP address so whatever IP you enter into it will be the one that it tries to use to connect to the network, im not too sure on what you can do to correct this as i am not that experienced with networks
4) Ive got no idea what using the THClite xips will do, you can try it if you want, if you do be sure to post what happens to let the rest of us know
5) I dont think there is a way to speed up the movement in the menus, have a look through the readmes and see if you can find anything
If im wrong on any of this let me know and ill look into it further and see what i can do for you