By donating bitcoin, you receive AGS. If you donated before March 1, then your AGS will give you BTS. There's no exact release date for bitshares, but it would surely not be after 120 days.
Yes you would have kept your PTS and got 1.3x BTS. For your AGS donated before March you will get 3.33x BTS.
PTS are like shares, when a DAC comes out you will get a share of that, see it as dividends