|Gut Voch. To my understanding, I think both riddles are addressed in Artscroll’s Rav Chaim Kanievsky on Chumash compiled by Rabbi Shai Graucher. Regarding the first riddle Rav Chaim points out that Rashi changes the order of the efforts, Doron, Tefilla, Milchoma. Rav Chaim points out that the order in the Pesukim is reversed with the hishtadlus regarding Milchoma first (when Yaakov divided the Machaneh), followed by Tefilla (Katonti) and then the Doron (which was Habah biyado). Rav Chaim explains that Rashi was telling the proper order of Hishtadlus in ordinary circumstances. However, Rav Chaim explains that in this particular case since the gift was from items he already owned there was no action needed until he was ready to actually send it. In contrast (and Rav Chaim doesn’t say it explicity in the Artscroll edition) that In Parshas Mikeitz, it doesn’t say Haba Biyado which indicates that more effort was involved in gathering the gift. Therefore the order was changed and Yaakov Avinu started to prepare that gift (Mizimras HaAretz) first.
Regarding the second riddle, Rav Chaim explains that the ruling of the Rambam refers to a grave within a burial ground. Because Rachel Imeinu was nifter on the way, and not burried in a formal burial ground people would have no way of knowing there was a grave there and could inadvertently become tamei and not realize that they should refrain from touching terumah and kodshim and from entering the Beis Hamikdash. In such a case a marker (‘nefesh’) would be required for all graves regardless of who is interred there.
I enjoy your shiurim very much.