I agree that it is not a bad beginning. It is hard to know what to recommend not knowing what you have access to.
For defense, I'd recommend starting with one brigade. Simpler to build and play and generally easier to make better without all the cards. From what you have listed, I'd pick black.
You have 17 spots for evil characters/enhancements and if you take out Rome that brings you to 18. Try to have a 1 to 1 ratio so 9 evil characters and 9 evil enhancements. An easy place to start here would be the rest of the black defense from the I starter deck. If you don't have enough Philistines then add the best of other black you have. A sub-optimal solid black defense will be better than the mix that you have. Of course adding Goliath, Philistine Chariot and horses, etc would be great but those tend to be expensive.
For offense: Fishing Boat, Philip and Bart, and My Lord and My God and Faith as a Mustard Seed would be helpful. Any other purple that you have? Almost all the purple offense that you want to use is from the disciples set or the starter deck. So if you get packs, I'd say disciples and you have a good chance of picking cards like Unholy writ or Joseph in Prison that helps your defense.