The first change in base line is evaluated as the glassy tempereture, it is not a peak necessarily . For furthur information you can watch this video on youtube.
As the two previous answers already point out you should not look for a peak so in my opinion none of your points 1-4 indicate glass transition. In heat flow there should be an step like shape going upwards in your case (endo up).
If it remains difficult to detect Tg with DSC i would suggest to use DMA which is more sensitive for Tg.
TSC (Thermally stimulated current) is the sole analysis , where the galss transition temperature is a peak. In DSC, the first change in base line is evaluated as the glassy tempereture.