Is there meila on the para aduma and mei chatas and is it debatable if the entire avoda and tahara of the para aduma was a function of hekdesh? Is it possible that it's simply a communal process that was performed by a kohein but really wasn't part of kodshim?
I know about the gemara that says that it's kdushas bedek habayis but I have a way to deflect that rayah. Any other rayos one way or the other?
The Mishnah in Masechet Parah 4:4 states “לעלם מועלים בה” that the parah is always subject to the issur of meilah. This is true until it is burnt to ash. See the Bartenura that states meila applies because the parah is referred to as a chatas.
Is it possible that it's simply a communal process that was performed by a kohein but really wasn't part of kodshim?
That wouldn't be dependent on whether there is meila or not. Kodshim Kalim are not subject to meilah until their blood is sprinkled on the mizbeach even though they are definitely part of kodshim.
The Rambam writes Me'ila 2:5
פָּרָה אֲדֻמָּה מוֹעֲלִין בָּהּ מִשֶּׁהֻקְדְּשָׁה עַד שֶׁתֵּעָשֶׂה אֵפֶר. אַף עַל פִּי שֶׁהִיא כְּקָדְשֵׁי בֶּדֶק הַבַּיִת הֲרֵי נֶאֱמַר בָּהּ (במדבר יט ט) "חַטָּאת הִיא". וּתְנַאי בֵּית דִּין הוּא שֶׁלֹּא יִמְעל אָדָם בְּאֵפֶר הַפָּרָה:
The prohibition against me'ilah applies to the Para Aduma from the time it was consecrated until it was reduced to ash. Even though its status is that of an entity consecrated for the improvement of the Temple, concerning it, Numbers 19:9 states: "It is a sin-offering." Beis Din made a condition that a person does not violate the prohibition against me'ilah with the ashes of the red heifer.
A proof that it is NOT a part of Kodshim but rather a communal process to obtain purity is that the Rambam places Hilchos Para Aduma in the halachas of Tahara and not in the laws concerning Avoda in the Beis Hamikdush.
