5. Metoro as a rule said kiore - henua at this glyph combination. All over the world sun was imagined as a 'climber' - as a small furry red mammal, mostly a cat. Personally I prefer the red panda:

"Its Western name is taken from a Himalayan language, possibly Nepali, but its meaning is now being worked on. One theory is that 'panda' is an anglicisation of poonya, which means 'eater of bamboo' ..." (Internet. Wikipedia)

But there was only one species of mammal on Easter Island, viz. the rat (kiore). 'Black rat' (kiore uri) was the name for one of the kuhane stations (Te Kioe Uri), a fact which indicates sun was nicknamed kiore; the end of the 4th quarter is the darkest time of the year:

The rat was sometimes pronounced kiore, sometimes kio'e (which latter often became simply kioe). It is no coincidence that Te Kioe Uri was the 5th station of the kuhane, because 5 is a symbol for 'fire' (another nickname for the sun).

6. As to Metoro's choice of the word henua instead of talking about the 'tree' there are several different alternatives. Most simple is just to accept his statement, implying that the rat is standing on the earth (the sun animal is not climbing the 'tree').

This is not so ridiculous as it first appears to be. To explain why is, though, no easy task. The best way may be to begin by referring to Manuscript E:

I suggest Kuukuu, the planter, is a playful name for the spring sun. It is he who is doing the important work, watering the plants with his rain and warming them with his rays. Kuukuu is the 'rat'. His rays are 'standing' on the earth.

In this view henua must be imagined as horizontal, not vertical:

7. Another clue is given by the kuhane breaking the kohe plant (Hatinga Te Kohe).

"Several Asian cultures, including that of the Andaman Islands, believe that humanity emerged from a bamboo stem. In the Philippine creation myth, legend tells that the first man and the first woman were split open from a bamboo stem that emerged on an island created after the battle of the elemental forces (Sky and Ocean).

In Malaysian legends a similar story includes a man who dreams of a beautiful woman while sleeping under a bamboo plant; he wakes up and breaks the bamboo stem, discovering the woman inside.

The Japanese folktale 'Tale of the Bamboo Cutter' (Taketori Monogatari) tells of a princess from the Moon emerging from a shining bamboo section. Hawaiian bamboo ('ohe) is a kinolau or body form of the Polynesian creator god Kane. 

An ancient Vietnamese legend tells of a poor, young farmer who fell in love with his landlord's beautiful daughter. The farmer asked the landlord for his daughter's hand in marriage, but the proud landlord would not allow her to be bound in marriage to a poor farmer. The landlord decided to foil the marriage with an impossible deal; the farmer must bring him a 'bamboo tree of one-hundred sections'. The benevolent god Bụt appeared to the farmer and told him that such a tree could be made from one-hundred sections from several different trees. Bụt gave the him four magic words to attach the many sections of bamboo: 'Khắc nhập, khắc xuất', which means 'put in immediately, take out immediately'. The triumphant farmer returned to the landlord and demanded his daughter. The story ends with the happy marriage of the farmer and the landlord's daughter." (Internet. Wikipedia)

The theme is the miracle of the fruitfulness of woman (mother earth). The 4 magic words 'put in immediately, take out immediately' can be understood if perceived from that direction.

To release the 'beautiful woman' is an act to be compared with Kuukuu working with his digging stick.

The bamboo (kohe) sections put together bit by bit explains the periods (sections) during which sun gradually rises higher and higher.