... Long ago in the very beginning of time there dwelt within a shell an infant god whose name was Ta'aroa. He was Ta'aroa the unique one, the ancestor of all gods, the creator of the universe whose natures were myriad, whose backbone was the ridgepole of the world, whose ribs were its supporters. The shell was called Rumia, Upset.

In Ca1-25 Tangaroa (kiore) could then be 'growing a new shell':

... Becoming aware at last of his own existence and oppressed by a yearning loneliness Ta'aroa broke open his shell and, looking out, beheld the black limitless expanse of empty space. Hopefully, he shouted, but no voice answered him. He was alone in the vast cosmos. Within the broken Rumia he grew a new shell to shut out the primeval void.

Possibly we should read Ca1-24--25 together. After having broken his primeaval shell, looked out and shouted in vain he decided to shut out the empty and limitless space. Ki te huaga ought to mean 'to the place (-ga) of fruits', which possibly means a return to the womb, but I cannot find huaga in my word list.

Kiore kikiu (in Ca1-18) could refer to how infant Sun (the 'Rat') was still securely tied up in the snares of Winter, 'squeeking' (shouting) for mercy:

Kikiu

Kikiu. 1. Said of food insufficiently cooked and therefore tough: kai kikiu. 2. To tie securely; to tighten the knots of a snare: ku-kikiu-á te hereíga, the knot has been tightened. 3. Figuratively: mean, tight, stingy; puoko kikiu. a miser; also: eve kikiu. 4. To squeak (of rats, chickens). Kiukiu, to chirp (of chicks and birds); to make short noises. The first bells brought by the missionaries were given this name. Vanaga.

Kiukiu (kikiu). 1. To resound, to ring, sonorous, bell, bronze; kiukiu rikiriki, hand bell; tagi kiukiu, sound of a bell; kikiu, to ring, the squeeking of rats; tariga kikiu, din, buzzing; hakakiukiu, to ring. Mgv.: kiukiu, a thin sound, a soft sweet sound. 2. To disobey, disobedience; mogugu kiukiu, ungrateful; ka kikiu ro, to importune. Churchill.

Kiore

Rat. Vanaga.

Rat, mouse; kiore hiva, rabbit. P Pau., Mgv.: kiore, rat, mouse. Mq.: kioē, íoé, id. Ta.: iore, id. Churchill.

... Maui took the sacred tresses of his sister Hina, he cut off lengths of Hina's hair and plaited it, to make a rope whose mana could not be destroyed by Ra. He took that noose of Hina's hair, he travelled eastward to the border of the sea; he placed his ropes around the pit from which the sun rises, waited there, he waited for the dawn. Then Ra came up, he came up from the spirit-world which lies in the east.

Maui pulled the cord, he caught the sun-god by the throat! Ra struggled, kicked, he screamed against the sky. 'Then will you go more slowly if I turn you loose?' The sun then promised Maui, 'Let me go, and I will move more slowly, I will make longer days for your fishing'. Since that time, men have had longer days in which to go about their work ...

One trick to make Sun slow down could be to insert 100 days before a new path of Sun was allowed to begin.