Iyar - the month of vav hachibur

1) Why could Aharon enter the kodesh kodashing only on Y"K?  B'makom she'baalei teshuvah omdim afilu tzadikim ainam yecholim laamod.  On Y"K, we are baalei teshuvah and can enter places that are off limits even to the greatest tzadikim the rest of the year. (Sefas Emes)

2) I had previously asked why in Dayeinu we say "banah lan es beis ha'bechira" when it is we who did the building -- it did not come down from Hashem.  (Thank you to everyone who responded with suggestions.)

Shir haShirim Rabbah right at the beginning:

יִצְחָק בְּרֵיהּ דְּרַב יְהוּדָה בַּר יְחֶזְקֵאל אָמַר, כְּתִיב (מלכים א ח׳:י״ג): בָּנֹה בָנִיתִי בֵּית זְבֻל לָךְ, בִּנְיַן בָּנֹה בָּנִיתִי. רַבִּי בֶּרֶכְיָה אָמַר, הַבַּיִת אֲשֶׁר הָיוּ בּוֹנִים, אֵין כְּתִיב כָּאן, אֶלָּא (מלכים א ו׳:ז׳): וְהַבַּיִת בְּהִבָּנֹתוֹ, מֵאֵלָיו הָיָה נִבְנֶה, שֶׁנֶּאֱמַר (מלכים א ו׳:ז׳): אֶבֶן שְׁלֵמָה מַסָּע נִבְנָה. בָּנוּי אֵין כְּתִיב כָּאן, אֶלָּא נִבְנָה, מְלַמֵּד שֶׁהָיְתָה הָאֶבֶן נוֹשֵׂאת אֶת עַצְמָהּ וְנִתְּנָה עַל גַּבֵּי הַדִּימוֹס.

Unlike Al Gore and the internet, we did not build it.  The Mikdash built itself miraculously.  We just went through the motions.

3) Sefer Yetzira says the month of Iyar corresponds to the letter vav.  Ain li eisek b'nistaros, but R' Tzadok gives us insight to understand it on some level.  Vav is the vav ha'chibur, the vav which connects.  Nisan is the month where we left Egypt with the goal of taavdun es ha'Elokim al ha'har ha'zeh.  Sivan is when we fulfilled that goal with kabbalas haTorah.  We need some way to connect the start of the process with its fulfillment.  That's Iyar, the vav ha'chibur between the two.

I would suggest as well that we know that this is the month when R' Akiva's students died because they did not treat each other respectfully.  There needs to be a vav ha'chibur between people, better connection between us to create more harmonious relationships.