I have to ask, which recovery are you using? Recoveries prior to 5027 had issues wiping cache, if I remember correctly. I use 5027 on my good phone cause it always worked properly for me.
The wifi issue sounds like when I changed the wpa_supplicant.conf which is in /data/misc.
You should always factory reset between ROMs and use tools like Titanium Backup to restore app data and message and call log info. If it started off broken then there had to be some data lingering somewhere. Which leads me to the recovery.
If 3G is broken, then you will have to return to stock and call Virgin and have them reset your data. I had this happen before. I was restoring a stock nandroid when I called and had to say "hold on I have to start the phone up, my battery fell out cause I was putting music on my SD card" ... "hold on it's booting up now" ... lol. Any way, if 3G works on fresh install then it may be an app that you are using that is causing all of this.
Well, that's my 2 cents, hope it helps.