Teclis' mount options are very strange. His basic "barded Ithilmar steed" which is supposed to be heavily armoured (like prince) only has light armour. This mount should be given +25 armour, and +50g making him 750g on this mount (the same change could be made for alarielles ithilmar steed mount).
He should be given a cheaper "elven steed mount" like the arch mages, with 90 speed and 25 armour for 700 with his other stats being the same as now.
His damn phoenix mount really should be reserved for campaign (make it a "campaign exclusive mount" for use in MP lobbies). Its addition defeats the whole theme of teclis being a squishy bad-in-melee super-mage. I really hope it's not too late for this and this bird has not already flown the nest.
A better flying mount for him would be something that only gives him mobility and not combat ability, like a pegasus, costing roughly 900g. A pegasus fits teclis much better thematically and would be better for HE balance overall.
(As a side note, high elf mages should have pegasus mount options much like how empire, DE, bretonnia and lizardmen have squishy flying options for their casters)
His main balancing issue (other than the phoenix) is the potion of charoi. Currently the base cost is 80g when it should realistically cost twice as much. I think the simplest way is just to increase its cost to 160g (If phoenix mount doesn't get removed then the potion should be unavailable on the phoenix).
A fun change would be to remove martial prowess from him (since he clearly has no martial prowess) and replace it with "Lileath's blessing" a special rule he had on TT. This could be a simple passive ability that reduces his miscast chance.