Looking at the WAB Hannibal book the Spanish were tribal falling under three major categories. In the north was an essentially Gallic culture so their forces were like the Celts. In the middle of the country were Celtiberians who were a mix of Celts and Iberian culture, the latter from the south and more influenced by Phoenicians and Greeks.
I think its the latter that you have, Mitch.
For Iberians WAB lists allow 25% for characters. Out of the remaining 75% for Iberians at least 50% were Scutarii, Caetrati and tribesman. The Romans tended to classify them by their shields rather than tribes.
Scutarii were unarmoured and armed with sword/ spear and large shield and jav. Some could have a heavy throwing spear. Their skills were feigned retreat and stealth (move through difficult terrain at normal speed - but their fighting ability is affected by fighting in difficult terrain, unlike Warband) . I'd say these are Light inf with some adaptations, definitely not warband.
Tribesmen was a type of levy armed the same as Scurarii but have Stealth and Warband so these are definitely warband types in LR2.
From this you could use your figures with larger shields as Scutarii or Warband.
Caetrati were sword, jav and buckler armed so were skirmishers but with good morale. WAB says max 1 Caetrati per 2 Scutarii.
Celtiberians were sword, spear and shield warband types.
Up to 25% could be cav. They had limited heavy cav (1 unit max) the rest light cav.
Up to 25% special units - Celtiberian warband or Slingers/ Balearic slingers.
Slingers were standard sling armed skirmishers. Balearic slingers were warband skirmishers who could fight as well as standard troops and had good morale. It says 1 Baleric per 1 Slinger unit as a max ratio.
Hope that helps.