Greetings of the sweetgrass of Tengoria to my dear brother Abilanedi,
This is a standard diplomatic greeting in High Elvish. Graduates from the same academy (here: the one in Argolake) usually address each other as siblings.
'Tengoria' is a general term for the area of Ansaf facing forward as the planet orbits, where clusters of shooting stars can be observed. The many points appearing to approach from a single distant source are thought to resemble an attacking Tengu spawning bodies as it dives. Here, it specifically means the more-Tengorian part of the greenstone steppes, where elves are thought to originate.
Your compliments astute,
balm lavender of sight:
this virgin desert's plight
and elders' clash are moot.
'balm lavender' - when the legendary hero Mortikesh traveled for three years collecting memories from shrines in the drybright and returned home, she was spurned. But after demonstrating the value of her new knowledge, her cracked feet were anointed with lavender.
Kef, my treasured land,
my most delicious tree.
In the stacked oaths' lee,
the river-bottom's planned.
The 'stacked oaths' are a tradition where elves leave memories of promises they have made, and the efforts they take to keep them, in important shrines. Swearing on the stacked oaths means that you will report your words to such a shrine no matter the outcome. This may be enforced or may be left up to the speaker's honor. The oaths that we have records of were almost always kept.
Zlatlan’s hubris tries
yet Torig’s dance ensures.
My people’s flow endures
when steadfast law applies.
'Zlatlan's hubris' - breaking with tradition, especially alone, far enough that you can't use memories of your predecessors for guidance.
'Torig's dance' - the principle that elves with similar jobs should be interchangeable.
Steel and water meet,
and unknown waiting twigs.
Kef, united, digs,
supporting one elph’s seat.
'unknown waiting twigs' - 'twig' is a common metaphor for a hypothetical path of conversation between an elph and their mental model of another. Here, Meikalani is using this meaning as a metaphor for areas of exploration in the real world.
'supporting one elph's seat' - splitting Kef into two towns, each ruled by one Magistrate, would be technically legal in Sota, but would be noticed as violating the spirit of the law.
A fire-spear arcs up
above my waiting hand.
Factions flinch and band
to fill my balanced cup.
'fire-spear' and 'cup' - props for a circus performance, a situation in which it's hard for one performer to smoothly take the place of another.
'factions flinch' - reference to a poem about the sudden development of animosity between the lieflings and kappas of the town of Picklebog, in North Mitan, specifically about suddenly seeing danger where you didn't see it before.
Come attend my shrine
or seek the darker ice.
Favored crews entice
and with my brother dine.
'darker' - deeper into the drydark.
'attend my shrine or' - 'either we can cooperate fully, or we can deal with each other honestly-but-not-forthrightly and must keep distance from each other.'
Power and vast wealth
await but claw and ear.
The merchants prosper here
and so does all our health.
'claw' and 'ear' - werewolves and catfolk.
Uniquely composed and expressed for the esteemed Abilanedi by his sister Meikalani.
Standard end of a diplomatic letter.
'expressed' - through ornate calligraphy, using a brush to apply glue, followed by multiple colors of fine sand.