Perhaps they could try "Ride On, King Jesus"?
If that's too old-school, there's Clarence McClendon's "I just came to Magnify" - it's uptempo, could be done mostly without solos, has lots of repeats and vamps, and has lyrics about praise and the line about rocks crying out, so that relates to Palm Sunday. The chords are a little complex, but it's basically two progressions repeating themselves over and over...just charted it out...
I Came To Magnify
Bishop Clarence McClendon & The Fire Harvest Mega Mass Choir
Intro -
(Single notes - g Ab a)|| Eb/Bb | Ab9(b5) | Bbm/G C7(b9) | Ab/F Eb/G Db9 || Fm7 Eb/G Ab6 Fm7| Eb/Bb C7(b9) | Fm7 Eb/G Ab6 Fm7| Eb/Bb C7(b9) | Fm7 Eb/G Ab6 Fm7| Eb/Bb Bb7 | Eb | (Single notes - Db c Bb c Gb f Eb )||
Chorus (2x) -
GbM7/Ab Ab7 GbM7/Ab Ab7
I came to magnify the Lord, praise His holy name,
Eb/Bb Ab9(b5) Bbm/G C7(b9) Ab6 Eb/G Db9
lift Jesus higher, lift Jesus high----------er,
Fm7 Eb/G Ab6 Fm7 Eb/Bb C7(b9) Fm7 Eb/G Ab6 Fm7 Eb/Bb C7(b9)
I just came to magni--fy, I just came to glori----fy,
Fm7 Eb/G Ab6 Fm7 Eb/Bb Bb7 Eb
I just came to praise the Lord!
(A13) GbM7/Ab Ab7 GbM7/Ab Ab7
(For He is) wor----------thy, worthy of all my praise. (sing 3x)
Eb/Bb Ab9(b5) Bbm/G C7(b9) Ab6 Eb/G Db9
Never will a rock cry out in my place, He's worthy of all my praise.
Fm7 Eb/G Ab6 Fm7 Eb/Bb C7(b9) Fm7 Eb/G Ab6 Fm7 Eb/Bb C7(b9)
I just came to magni--fy, I just came to glori----fy,
Fm7 Eb/G Ab6 Fm7 Eb/Bb Bb7 Eb
I just came to praise the Lord!
Vamp - (6x)
Eb/Bb Ab9(b5) Bbm/G C7(b9) Ab6 Eb/G Db9
Never will a rock cry out in my place, He's worthy of all my praise.
Vamp - (2x)
Eb/Bb Ab9(b5) Bbm/G C7(b9) Ab6 Eb/G Db9
Never, never, never, never,
Fm7 Eb/G Ab6 Fm7 Eb/Bb C7(b9) Fm7 Eb/G Ab6 Fm7 Eb/Bb C7(b9)
I just came to magni--fy, I just came to glori----fy,
Fm7 Eb/G Ab6 Fm7 Eb/Bb Bb7 Eb
I just came to praise the Lord!
KeyPlaya did a chorded version on LGM, too...