[Note: It should be understood that the account foretold by Moses of the “servants” who would come down to bow before him (not Aaron) is a separate event from Pharaoh’s summons for both Moses and Aaron. The servants are not said to mention anything about Pharaoh’s summons after the death of the firstborn, and their act to implore Moses to leave Egypt is a separate matter from Pharaoh’s final act of banishment from Egypt.
Also, in reference to Exodus 10:28-29, it is not talking about Moses and Pharaoh not ever seeing each other again, but rather it is Pharaoh’s point to tell Moses to not get the idea to again come before Pharaoh to plead Israel’s case, when he said, “take heed to thyself,” and it is this context in which Moses replies to Pharaoh, that he would not come again to plead and negotiate the release of the Israelites, and confirms that he would not “see thy face again,” which is not said to be the words of God, but those of Moses.
The context for the bitter outburst is one where Pharaoh tells Moses that he will no longer grant audience to Moses, and there will be no more continuation of the negotiations that had been transpiring from plague to plague, and as we see in the final plague, there was no negotiation, but rather a summons and banishment proclaimed by Pharaoh. Therefore, the only means by which Moses could again come before Pharaoh was by an official summons, which he and importantly Aaron received in the period before daybreak on the night of the Passover, following the death of the firstborn.
Keeping in mind that the prohibition to leave the door of the settlements was a command from Moses to the people of Israel, and not one directed to Moses and Aaron from God, noting also that Moses was not a firstborn, and the “destroyer” had already passed over Egypt.]
[Note: For the burning of the sacrifice, it is presumed that the remains of the sacrifice were placed to be burned before the death angel passed over Egypt and over the Israelite settlements, and what remained to be burned up was to be consumed in the fire in the “morning” hours, understandably before dawn and certainly before sunrise.]
[Note: According to Adam Clarke the yearling was taken from the sheep, or from the goats as “the שה seh means either; and either was equally proper if without blemish. The Hebrews however in general preferred the lamb to the kid.” And Scripture states that “Your lamb shall be without blemish, a male of the first year: ye shall take it out from the sheep, or from the goats: And ye shall keep it up until the fourteenth day of the same month: and the whole assembly of the congregation of Israel shall kill it in the evening (Ex. 12:5-6).]
[Note: Some conclude that Pentecost is to be held on a Monday based on the way a person counts 50 days from the “morrow after the Sabbath” (Lev. 23:15), and the key word is “from” and what it means in regard to how to count the days to Pentecost. The Hebrew word, ‘min’ (“from”), is a term that is inclusive respective to time, and so the phrase “from the morrow after the Sabbath” means to include the day of Sunday as the first day in the count, not Monday. This is speaking of the Sunday that comes after the weekly Sabbath that usually falls between the two holy convocations associated with the Festival of Unleavened Bread.]
[Note: Among some Rabbinic and Christian conclusions the phrase “between the two evenings” has come to mean a period of time from early or late afternoon until sunset on the same day, and also a period of time from the sunset beginning the 14th day to the sunset beginning the 15th day (Nissan), which leads to the conclusion that the Passover was slain in the daylight portion of the 14th day in the late afternoon and was eaten on the night of the 15th of Nissan.]
[Note: The observances noted in Leviticus 23 are called the “fixed times of the Lord” and the “sacred occasions” in the Tanakh. In the Authorized Version of the Bible we know them as seasons, holy convocations and feasts, and in this context the relative starting and ending dates of the days of unleavened bread are not given to us in Leviticus.] 
(Working Through the Unleavened Bread Issues–Part One)