I finished with the Magyar tech tree. Use it at your own risk.

Magyars
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Note: the Magyars lived in tents called jurta, plural jurták. This is important to all the 'buildings'.
- Shrine to Úristen (+10 happiness, requires town), Sacred groove of Úristen (+20 happiness, requires large town), Sanctuary of Úristen (+30 happiness, requires city).
- Shrine to Boldogasszony (+10 happiness, requires town), Sacred groove of Boldogasszony (+20 happiness, requires large town), Sanctuary of Boldogasszony (+30 happiness, requires city).
Note: Úristen means word by word 'Godlord', Boldogasszony means 'Happywoman'. We have only traces of the old religion.
If you use the RTW type shrines Úristen should be a law-type god, and Boldogasszony a fertility or mother type goddess with public health bonus.
Note: Ancillary (priests to both): Táltos (+1 influence, +1 public health, maybe a little healing after battles)
Note: the old god were called later 'the god of the Magyars'. We don't know any personal name to Him, maybe He hadn't any.

(- Forest clearings (+5 farming, available from start in most provinces - high bonus to indicate how an important improvement this step means compared to no farming buildings), Farms (+8 farming), Crop rotation (+11 farming).)
- Bigger and bigger herds: (more and more 'farming' bonuses)
Note: in the Steppes there weren't large forests and in this era the Magyar agriculture was not such great.
Note2: all the nomadic people had limited agriculture instead of great farms they had many herds.

- Paths, Mud roads
Note: does they mean the basic roads? I suggest level 1 roads.
- Trader (+20% trade), Market (+40% trade), Merchant (+60% trade)
- Port, Shipyard
- Blacksmith (+1 to all weapons, requires Iron resource), Master blacksmith (+2 to all weapons, requires Iron resource), Armorer (+1 to all armor, will NOT require blacksmith in order to be constructed), Master armorer (+2 to all armor)
- Salt mine (+1 mining), Large salt mine (+2 mining), Copper mine (+2 mining), Large copper mine (+4 mining), Silver mine (+3 mining), Large silver mine (+6 mining), Gold mine (+4 mining), Large gold mine (+8 mining). All mines require their respective resources in the province in order to be possible to build.
- Wooden pallisade, Wooden wall, Large wooden wall (possible to move on top of it), Stone wall (possible to move on top of it)
Note: the nomadic people didn't build walls, but if others are able to build the Magyars should, too.
- Muster field (slav axemen (servants) with lower stats (like at Schytians), slav spearmen (servants) with lower stats, peasants if you use them)
Note: the servants' weapons should be cheap, but I can imagine any type of them.
- Practise target [may called also Bowmaker] (+1 missile weapon xp), Archery range (+2 missile weapon xp), Masters of Archery (+3 missile weapon xp)
Note: I put here the 3rd level. It does not need Bowmaker.

- Stables (Magyar horse archers {Magyar lovasíjászok} [light horse archers, no armor, spontoon {fokos- see the pictures}, fast, good stamina], Kopjások [medium cavalry, sabre, bow, lance, shield], Chosen Magyar Horse Archers {Válogatott magyar lovasíjászok} [sabre and bow, very-very good leather armour, elite, good stamina- the same like the Scythian nobles]. But the noble word is anachronistic in this era.
Knights {Lovagok}: western type knight unit, ZOR in all the western Catholic territories including Hungary. They should be cost 20% more than their reasonable value.
Note: I don't see any reason separate the Magyar, Kabar and Székely horse archers. In the text can be written to mention their nations. They should NOT be ZOR armies the Magyars in the game can settle in any part of the map.
Note2: I didn't find anything about some heavy cavalry from the 9-10. century. If the player want them he can hire mercenaries.

- Cavalry training field (+1 to cavalry xp, requires Stables), Cavalry training grounds (+2 to cavalry xp, requires Cavalry stables)

Instead of more happiness buildings (I cannot imagine anything.) I suggest an ancillary, the 'Regös'. It is like the celtic bard, and should give +1 influence and +5 happiness. They should come very easy. Otherwise the Tavern is acceptable. Sometimes one have to accept the unacceptable.
I suggest in general the Magyars should be at a power level 30-40% of the Khazar empire.
Representing the raidings Magyar horse archers (rebels) may appear in the western countries and in Byzantium.
Symbolizing the Magyars who remain in the eastern Steppes can be rebels in Etelköz, Levedia (the 2 original M areas) and in the Caucasus (the Szavárd Magyars).