Blue first, so it was easy.
4th creature will be needed if T.rex first, and I have not think about it yet.
Phorusaura's Atk should be 1017 or higher, to take down Blue.
Yesterday I did the tower but without recording.
Team:
Lv15 Erlokogamma
Lv16 Dracorex Gen 2
Lv20 Alankylosaurus
Lv22 Quetzorion
Process:
Gamma as my first creature and Blue as opening.
Swap-In Alanky, kicked Blue without LI (a crit landed), and be sacrificed on T.rex.
Gamma in, DD + PP to cut T.rex HP, and AI swapped, MSS landed on I.rex.
RAR + Swap-In Draco, then brought Gamma back, to took down those two.
...
https://www.youtube.com/watch?v=KMLu5f6nKYg