I found it. It's an Ibn Ezra in Shemot 8:22.
ולפי דעתי כי אנשי מצרים בימי משה היו על דעת אנשי לנדיא''ה שהם יותר מחצי העולם וכלם הם בני חם ואינם אוכלים בשר עד היום. גם דם וחלב ודג ובצים.
Meaning that the Egyptians didn't eat any meat, milk, fish, or eggs. Doesn't mention salt, but the Minhage Yeshurun didn't imply the Ibn Ezra mentioned anything about salt....
First of all, see here, in particular my answer (yes, shameless plug...):
Small Seder Ideas (5780)
I would recommend using two different intellectually probing Hagados, one for Seider numero uno and one for Seider numero dous, preferably one that attempts to string and explore connections in the Hagada. Additionally, prepare for the Sidarim in advance: ...
Along with the classic raffles, props, and candy, I always found that if the Baal HaSeider is excited, the children (who the Baal HaSeider has a Mitzvah to be there for ;-)) will mirror that excitement.
Additionally, a good friend of mine reenacts Pesach Mitzrayim at their Seider: they cover their doorpost in parchment paper and then spread tomato ...
Opening the Door and Pouring the Kos for Eliyahu - Demonstrations of Emunah says at minute 9:20 that we open the door to show that we have absolute faith that it is a ליל שימורים, a night of protection. This is a matter of ruchnius rather than explicit physical protection. This ליל שימורים prevents the mazikim (spiritual enemies) from causing harm. One ...
These poems might be of interest to some people:
Exploring Passover through Contemporary Israeli Poems
Found on the web (in two sets):
As you mentioned, there are obviously an infinite number of Haggadahs. The first one that comes to mind would be the Chinuch Haggadah - Expressing and transmitting the splendor of our Mesorah by Rabbi Yaakov Bender. From your question this sounds like it would be the best fit (and it ships free if you order it by the 31st).
If it is not what you're looking ...
I recommend the second person advice of which this all stems (Exodus 13:8):
וְהִגַּדְתָּ לְבִנְךָ בַּיּוֹם הַהוּא לֵאמֹר בַּעֲבוּר זֶה עָשָׂה יְהוָה לִי בְּצֵאתִי מִמִּצְרָיִם׃
And you shall explain to your son on that day, ‘It is because of what the LORD did for me when I went free from Egypt.’
Meaning, as it seems, your grasp is already decently ...
UPDATES: Rav Shlomo Amar stated in a letter that tehre is absolutely
no basis to this heter and that it is wrong. It has been communicated
to Rabbi Hoffman that 3 of the Rabbonim who signed have retracted the
ruling (Rav Moshe Suissa, Rav Aharon Cohen, and Rav Yonatan Sror).
The ruling was, apparently, issued only in one case of a ...
I'm not sure this quite answers your question, but Radvaz (3:584 (1012)) does seem to question Rashbam's anatomical facts, and says something that might be considered answer:
ועוד ראיתי כי הסימנים שוכבין זה על זה ולא ידעתי אם סימני אדם נשתנה
Depending on how you read this, he could be entertaining the possibility that the anatomical facts had changed ...