I dont think you should play the Carthies as if they were Greeks. You have to use the local troops and mercs to get the real enjoyable flavour of a campaign with them with only a few citizen/elite units available in overseas campaigns.

And as for not having peltasts - there are a great many Iberian unit types that can fulfill that role. They might not be quite as good in melee as the Greek version but they are better at the javelin bit.

Also, you will find yourself rolling in money compared to most campaigns, so elephants and those mega-expensive elite ships become affordable - and a necessary expense to stop corruption - soon enough.