If I wake up early to learn (before Alos hasachar), do I need to wash my hands again after Alos before I daven shacharis?
Yes you should wash your hands again after alos hashachar, however you will not say al netilas yodayim afterwards. The reason for this is because there are opinions that the ruach ra goes off at alos, therefore you should wash your hands again. You will not make a bracha though, because one of the reasons for washing our hands is because when we wake up we are like a new person, and we are now started the new day and going to daven. Since you already did that. therefore you would wash again without saying the bracha.
O:CH 4-14, M:B ibid 31-34.