Theodore Marier has also written a nice chant version (see attached).

It's also called In Paradisum.

Actually it's the Subvenite or another responsory from a list of about 8 options, sung in the position traditionally held by the Libera me.

Bugnini's Requiem is in many ways a travesty

Here is my transcription of the original In Paradisum into simplified, stemless modern notation, as well as a transcription of the original chant into english using the translation from the Parish Book of Chant. Free to use and share.
https://psallitedomino.com/blog/free-transcription-in-paradisum

I have been in the habit of singing it in english, and then repeating the original at our Novus Ordo parish. I've had multiple parishioners tell me how much they like this chant and how peaceful they find it—with one emphatically stating he wants it at his funeral. This was such an interesting response to me because this was something the parish had not heard in decades and yet they responded to it immediately. It's almost as if... Holy Mother Church has some ancient and perennial wisdom that transcends time or something...

Or Adam Bartlett's chants here?

Ah, this is what we've done in the past! Thanks! (The Weber looks nice too though.)

Rich enough,

In the new rite, the Subvenite has been moved from the entrance into the Church to the Final Commendation at the end of Mass. the Libera Me is not found in the 1974 Graduale Romanum; evidently it is no longer part of the funeral liturgy.

What further need have we of witnesses?

Where does the title “Song of Farewell” come from? I've never heard of before, and I can't find it in any of my books in Latin or English.

I second Fr. Weber's Saints of God - based on the Subvenite. I use it often.

In the new rite

key give away

The Libera me is on p.696 of GR, still (as an option) for the Final Commendation and Farewell

That's a different Libera me... The Libera me, which begins "Libera Me, Domine, de morte aeterna" is excluded from the reformed Roman liturgy.

All that being said, I'm fairly certain (I don't own a copy to confirm) the rubrics at that point in the liturgy say something along the lines of "one of the following, or another suitable song".

Who's to judge that Libera me ... de morte is unsuitable as an alternative?

“another suitable song"

Oh ... you have got to simply love and give thanks to the almighty above for that all pervasive and endlessly destructive (oops,,, I meant creative!) three little word rubric. I am so glad we have this. With it we can program anything, anywhere at any time! We can legally suspend anything legal or illegal to our personal satisfaction. How absolutely clever is THAT!?

SVVLBHCOM

SVVLBHCOM

?

"another suitable song," is NOT a simple three word rubric, even in this mistranslation into English it has an attached definition of suitability. In Latin it says "another chant/song which is suited to ... , and ..."
However the bishops, particularly in the USA, flagrantly disregarded the spirit of the rubric, which gives them an explicit responsibility for the text of the song/chant.

Yes, "suitable" is the operative word. I believe the Latin original is "alius cantus aptus." Aptus is the operative word and cannot be construed to mean merely "another desired song."

Consider these lyrics from a song that OCP is touting on its website today as a song of farewell, which is assuredly not "suitable/aptus." The lyrics implicitly canonize the deceased:

Go in peace, God be with you
Go in peace, be at rest
With the saints and the angels.
Now you are free.
Go in peace.

See, the Father is waiting
With a robe of white, purest white.
Go and feast at his table
With the bread of life, bread of life
Lift your heart, rejoice and sing for you are home;
Home at last and forever in the arms of the holy one.

Many theological and doctrinal problems with this text. As I said, it implicitly canonizes the deceased, which departs from what the Mass of Christian burial prays for. It also refers to feasting on the bread of life in heaven, but in heaven there are no sacraments because the Beatific Vision makes sacraments superfluous.

https://www.youtube.com/watch?v=hKWJEUx40eA

When the publishers are pushing unsuitable music, it's time to call them out.

francis, surely nothing can justify the abuse of liturgical norms.

48. Peragitur autem a schola et populo alternatim, vel simili modo a cantore et populo, vel totus a populo vel a schola sola. Adhiberi potest sive antiphona cum suo psalmo in Graduali romano vel in Graduali simplici exstans, sive alius cantus, actioni sacræ, diei vel temporis indoli congruus,55 cuius textus a Conferentia Episcoporum sit approbatus.

48.This chant is sung alternately by the choir and the people or similarly by a cantor and the people, or entirely by the people, or by the choir alone. In the dioceses of England and Wales the Entrance Chant may be chosen from among the following: the antiphon with its Psalm from the Graduale Romanum or the Graduale Simplex, or another chant that is suited to the sacred action, the day, or the time of year,55 and whose text has been approved by the Conference of Bishops of England and Wales.

The text is still not perfectly clear, since the punctuation of the Latin shows that it both suited to the action (eg an offertory procession) and adapted to the character of the day or the season (a green Sunday, or your solemnity of title).

Who decides if anything is “suitable” or not?

There’s a reason imprimaturs used to be a thing, and the rubrics do mention “approved by the local ordinary or conference of bishops”, so technically, they should decide, although arguably it’s probably a good thing they are as impotent as they are these days… what little they do agree on tends to be pretty vapid, God bless them.

Well, back in 2006 (early in B16's pontificate) the US bishops decided that if there was going to be a decider it would be the ordinary of the jurisdiction of publication, which meant the Abp of Chicago (GIA and, formerly, WLP), the Abp of Portland in Oregon (OCP), and the Bishop of St Cloud (Liturgical Press) were given the lion's share of authority in practical effect, and Rome never got back to them on that.