Speculations on pea-green and runcible

The Owl and the Pussy-cat went to sea

In a beautiful pea green boat,

They took some honey, and plenty of money,

Wrapped up in a five pound note.

The Owl looked up to the stars above,

And sang to a small guitar,

'O lovely Pussy! O Pussy my love,

What a beautiful Pussy you are,

You are,

You are!

What a beautiful Pussy you are!'

II
Pussy said to the Owl, 'You elegant fowl!

How charmingly sweet you sing!

O let us be married! too long we have tarried:

But what shall we do for a ring?

'They sailed away, for a year and a day,

To the land where the Bong-tree grows

And there in a wood a Piggy-wig stood

With a ring at the end of his nose,

His nose,

His nose,

With a ring at the end of his nose.

III
'Dear pig, are you willing to sell for one shilling

Your ring?' Said the Piggy, 'I will.'

So they took it away, and were married next day

By the Turkey who lives on the hill.

They dined on mince, and slices of quince,

Which they ate with a runcible spoon;

And hand in hand, on the edge of the sand,

They danced by the light of the moon,

The moon,

The moon,

They danced by the light of the moon.

I have had, for the past three days, twirling wickedly in my head, the above quoted Edward Lear rhyme "The Owl and the Pussycat." Surprisingly (to me), most of my acquaintances have never heard it. And it's not because I'm old! Many of them are older than I.
In any case, I am wondering:

1. What was Lear's obsession with pea-green? And how can anyone define it as beautiful?
2. Runcible? I suppose if you're making up words, runcible is as good as any, but it doesn't seem to have caught on the way, say, google has.
3. Did pussy have the same double entendre back in 1871 as it does now?

Still, even if you cannot answer a single question, I can take satisfaction in knowing that at least some of you are humming the damn thing now.