I have MIUI 1.5.27 on my EVO 4G. I checked all the 3 points you posted but didn't get any FC, maybe can help if you go recovery, wipe cache & dalvik, then reflash MIUI. I had CWM recovery before and for any reason my roms had a lot of FCs, then I changed to Amon-RA 2.3 and never had a FC again.