Alleluia, Sing to Jesus, is a hymn for Holy Communion. If you examine the words, it is a better fit for Communion. OCP just does not get it.
A lot of the songs that you have just do not fit the Easter Season. That is really sad. For the Second Sunday of Easter, you should have sung “O Sons and Daughters” since the verses fit with Jesus and St. Thomas.
You could very well continue singing “Jesus Christ is Ris’n Today” as well as “At the Lamb’s High Feast We Sing”, “Now the Green Blade Rises”, “Sing with All the Saints in Glory”. Other hymns that your choir could sing include “Draw Us in the Spirit’s Tether”, “Let All Mortal Flesh Keep Silence” and "Shepherd of Souls’ (which would have certainly been most appropriate for Good Shepherd Sunday.
Now, depending on your diocese, the Sunday before Pentecost will probably mark the Ascension. A great hymn would be “A Hymn of Glory Let us Sing” sung to the tune of All Creatures of Our God and King. Then, you could very well pair this with “Alleluia, Sing to Jesus” for Communion. You could end the Mass with “Go Make of All Disciples”.
Why are you guys not singing “Come, Holy Ghost” for Pentecost? It is the Traditional Hymn of the Church (it is a translation of Veni Creator Spiritus). The recessional could also be “Go, Make of All Disciples.”
There is an Englisih translation of the Regina Caeli which is set to the tune of the Latin chant and is not very difficult to sing.
I would seriously look into getting Proulx “A Community Mass” setting. You can find it in the GIA Worship III hymnal. It is faithful to the text and is easy for both a small choir and a congregation to sing. Remember that the Gloria, albeit all of the acclamations and prayers of the Mass, need to be faithful to the approved texts. They cannot be paraphrases.
I am also leery of using anything by Cat Stevens (melody of Morning Has Broken). Some of the worst music has come to us from the 1970s, early 1980s, which, unfortunately, is the time period where MI is stuck. I would also run, not walk, away from anything that Bob Hurd writes as his music is too vertically-oriented.