A riddle of companions

Question

With none, I am short and may be late
With one, I am folk, local to a place
With two, behold me! Never first
With six, and I am made with curd
With seven, I’ll keep you off the ground
With ten, alone with water all around
With eleven, you could say I’m a friendly fish
With thirteen, I refer to me, so selfish
With sixteen, I want you to be vegan please?
With twenty-three, I’m too heavy to fly with ease
With twenty-six, I’m six but also seven
But wait, there’s more than just the above eleven
With certainty I am as yet unknown
With a draft, short, I can help stop you groan
With ratio, I am made by a guy
And with this final line I ask what am I?

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There is a clear and unique answer which you will know when you have found it.

Answer 1

I think you may be

Eta

With none, I am short and may be late

Eta is a short Greek letter.
ETA stands for Estimate Time of Arrival

With one, I am folk, local to a place

Aeta = people indigenous to mountainous parts of Luzon.

With two, behold me! Never first

Beta = second letter of the Greek alphabet

With six, and I am made with curd

Feta = a type of cheese.

With seven, I’ll keep you off the ground

Geta = a wooden clog.

With ten, alone with water all around

Jeta = island in the Bissagos Islands

With eleven, you could say I’m a friendly fish

Keta = a type of salmon

With thirteen, I refer to me, so selfish

Meta, this clue is self-referential

With sixteen, I want you to be vegan please?

PETA

With twenty-three, I’m too heavy to fly with ease

Weta = a flightless cricket

With twenty-six, I’m six but also seven

Zeta = sixth letter of the Greek alphabet, seven in Greek numerals

But wait, there’s more than just the above eleven
With certainty I am as yet unknown

Eta can be an unknown in maths
Edit: Should be Theta, a sort of contraction of the eta (thanks OP).

With a draft, short, I can help stop you groan

Aceta where AC is short for Air Conditioning,

With ratio, I am made by a guy

Possibly Pieta (by Michaelangelo) where pi is the ratio of a circle's circumference to its diameter.