Did the avos shake lulavim, put on tefillin, remember amalek, or take maaser?
According to what we learn that the Avos, or at least Avraham Avinu, kept the Torah there is no reason to think that he didn’t keep Lulav. The Tanya writes that Yakov Avinu would do Tefillin through a meditation with sticks. This is because, as was said above, the Avos learned the secrets of the Torah and its reasoning, and then decided how to manifest these ideas into action.
This being the case, perhaps by the Avos Tefillin and Lulav where one and the same.
Amalek obviously couldn’t be forgotten before he existed, but the concept of hating Hashem’s enemies was around all along. This was the point of a few Nesyonos of Avraham Avinu.
Maaser is in the Pasuk. Avraham Avinu gave Maaser to Malki Tzedek and yaakov promised to give Maaser upon his successful return to Eretz Yisroel.