I am seeking to understand the kabbalistic meanings of the following biblical persons:
1) Esav. Does he represent tohu chesed or klippot chesed?
Would appreciate Sources With Your answer.
The Baal HaTanya in Torah Or describes Lot as:
קודם הבירור הי' לוט כלול באברהם בקדושה כמו סיגים אשר קודם הצירוף ובירור מעורבים הם עם זהב. ולו"ט בגי' מ"ה אחורי' דשם מ"ה. אך הוא מקור חו"ב דקליפה לכן נק' לוט לשון קללה ולכן הלך לוט את אברהם קודם הבירור
Before the purification, Lot was included in Avraham in holiness, like the impurities prior to the parting and purification which are mixed in gold. Lot (Lamed Vov Tes) has the numerical value of 45 representing the rear of the Name Mah [A way of spelling out each letter of the Tetragrammon to total a numerical value of 45]. But it (Lot at that level) is the source Chochma and Bina of Klippa, therefore he is called Lot related to the word curse, and therefore Lot traveled with Avraham before the purification.
In that place he alludes to Eisav having a similar relationship to Yitzchak. In another place he expands on that. Quite a bit more technical than the above, but in summary Esav represents the level of Klippah which allows energy to be drawn from Kedusha without being affected by it - the 11th level, whereas Sefiros in Kedusha number 10 only.
The discussion offered by @Yishai above is accurate. For a detailed discussion of the concept of Lot and his two daughters, see Likuttei Torah of Chaim Vital, parshat Vayera, the discourse, "And Sarah denied that she laughed" starting from paragraph 6.
As mentioned in Meori Ohr, Letter Lamed, chapter 27, it emphasizes 'cursed' and not 'to curse'. Lot is cursed because his two daughters become for him the parallel to Leah and Rochel for Yaacov. Meaning they become his wives.
Esav on the other hand is associated with the nachash in Meori Ohr, Letter Ayin, chapter 68. Esav עשו, is נחש חי, living serpent. He is also related to his ministering angel on the side of klippah, Samael (סמאל). This is because the letter Samech is exchanged with the letter Shin. Then include the letters and kollel.
This function of the nachash is relating to the nachash of kedusha, meaning before the sin in the Garden of Eden. This is also discussed at length in Leshem Shevo v'Achlama, Sefer Deah.