My first idea is this, available for all choices, essentially summonable in the same way as the Soviet conscripts.
1CP - Call in a squad of Romanian infantry. 5 men, tough as Volksgrenadiers but less accurate and slightly slower, equipped with mauser rifles. May be upgraded with a ZB26 light machinegun (similar to Bren gun) and Molotov cocktails. Can dig slit trenches and erect ZB53 MG nests for 200 manpower.
Cost 260 manpower.
My ideas for the trees themselves are:
Flank Guard (defensive)
1CP - Backs to the Wall. Soldiers will make a last stand, improving damage and toughness at the cost of movement. Costs 100 munitions to activate. Lasts 40 seconds. Active.
2CP - AT support. The Romanians will call in a TACAM T-60 tank destroyer. About as tough as the T-70, with the same penetration as the Marder II. Can fire specialised ammunition to improve penetration. Costs 350 manpower.
2CP - Air support. A Hungarian air force Macchi fighter will strafe the area for 30 seconds. Costs 100 munition.
2CP - Scavenge resources. Increases the level of munitions and resources by 40%, but slows down manpower by 40%. Costs 100 munitions. Active.
Support the Attack (offensive)
1CP - Call in a squad of Hungarian infantry. 4 men, armed with Mannlicher rifles, similar in stats to Grenadiers. Can be upgraded with Danuvia SMGs (similar to Thompsons), may use stick grenades and dig foxholes. Costs 320 manpower.
2CP - Charge! All infantry move faster and take much less suppression, but are more susceptible to damage. Costs 150 munitions. Active.
3CP - Call in a unit of Vanatori. Elite Romanian mountain infantry. 4 men, armed with mauser rifles and ZB26 LMG, and can use Haftholladung AT grenades. May be upgraded with Beretta 38 SMGs (again, similar to Thompson). Similar stats to Assault Panzergrenadiers.
3CP - Call in a Zrinyi 43M assault gun. Similar to Stuh 42, may be upgraded with anti tank ammunition to improve armour penetration.
Occupation Forces (multirole)
1CP - Anti partisan duties. All infantry gain 50% line of sight and can hide in cover. Passive.
2CP - Acclimatisation. Infantry gain better protection from cover or buildings and work better in snow and woodland. Passive.
2CP - Local liaison. Manpower production is increased by 40%, at the cost of fuel and munitions production being slowed by 40%. Active.
2CP - Leadership. Call in a Colonel and two staff officers. 3 man squad, Colonel with pistol, staff officers with Danuvia SMGs. Similar stats to Ostheer Skirmish officer. May call in light artillery and rally troops. Cost 280 manpower.