Starting out in Infamy Infamy - some figure advice please

[dadlamassu]

Santa brought me a set of "Infamy, Infamy!" rules and cards.  I have read them through (once) and have decided to adjust my collection to play some games.  Now I have sufficient models to cover: all units in the Britons and Gaul lists, almost all units in the Early Imperial Roman, some units for the Late Republican Romans and none specifically for the Germans.  My figures are mainly Agema, Aventine, Black Tree Design, Warlord Wargames Factory and Wargames Foundry with a smattering of others. 

The advice needed is for suitable figures, ideally plastic but metal is fine, for:
Late Republican Romans:
1. Expediti (Expedites?) - described as light infantry with mixed weapons - thinking of using my velites the ones not wearing wolf skins
Early Imperial Romans
2. Cohors Urbanae - described as Heavy Infantry with Pila - how to make them different from my Warlord Legionaries?
3. Roman ex-Legionary Colonist - described as light armour with mixed weapons
Germanic Tribes - familiar with the Warlord, Foundry and Black Tree ranges though the latter seems to have deleted the Ancients figures.  This thread has helped
http://leadadventureforum.com/index.php?topic=128735.msg1629333#msg1629333
4. Foederati Infantry - described as medium armour mixed weapons, shields "Roman Style" - I suppose armoured warriors with bits of Roman kit from their unit would do?
5. Foederati Cavalry - described as medium armour mixed weapons - I suppose armoured warriors with bits of Roman kit from their unit would do?

Thank you in advance for any ideas on sources, conversion ideas etc.