Your body maybe a little sensitive to the minoxidil or maybe even the PPG iin the mix.
Try applying it once a day(at night) for a few days and see if your OK. Then try moving up to twice a day when your body is used to it. I did this and I found that I had no irritation at all. Maybe I'm lucky but I had no itching, flaking, dandruff, residue and only a minor shed.
If you continue to react badly to it there is a possibility that:
1. you are allergic to Minoxidil (very rare)
or
2. you are allergic(or irritated) by the PPG in the Rogaine
If you feel it could be the PPG, you could try Dr Lee's PPG Free 5% Minoxidil, he uses Glycerin instead of PPG as the vehicle to absorb the Min into your scalp.
If you still get the symptoms after using Dr Lee's Min, I would say you should bin the Min and stick with Finasteride and Nizoral and hope for some thickening and regrowth with those. It would be a hell of a lot less hassle to pop a pill daily and wash your barnet with some pink sh*t 2 or 3 times a week.
That should sort you out unless your one of the 1% that turns into a homo.