Go for Favored Soul/Stormlord/Blackguard. You don't need Fighter levels, because depending on your race, you will get a multiclass xp penalty.
Also the Paladin/Blackguard is not possible unless you make him fallen.
In general, a Favored Soul/Stormlord/Blackguard is far better than Paladin because you get more and better spells, sooner.
If you pick a deity with the spear, you get Weapon Focus with it for free.
A good example is Talos, the Storm Lord.
Which fits perfectly per lore and gameplay wise.
Spellcraft is actually not that necessary unless you want to get epic spells which aren't needed. In the expansion you get a bunch of casters which they can handle the epic spells for you.
So, Concentration, Diplomacy for the OC if you want to but if you play Evil (Blackguards must be evil and Talos need you to be CN, CE or NE) you can just kill everybody.
If you don't like Diplomacy, go with Spellcraft and put cross class skills in Hide, not many are required.
Also, you want Power Attack, Cleave and when you get the third Blackguard you get Turn Undead which can be used for Divine Might (CHA to damage).
You don't need Wisdom at all, so leave it at 8 or 10, it doesn't matter, your saves will be great with FS and Blackguard and buffs.
You might want Monkey Grip to use a shield with your spear also but it gives you -2 to attack.
For spells, pick ONLY defensive and healing spells. Don't bother with summons or offensive spells that have Save: No in their descriptions.
You basically need things like Protection from Evil, Shield of Faith, Nightshield, Greater Magic Weapon, Magic Vestment (cast it on both armor and shield) as well as anything that protects you or makes you stronger.
Divine Power is essential, try getting the Extend Spell feat and cast it all the time. You can also pick stuff like Raise Dead/Resurrection/Heal/Regenerate/the Restoration line etc.
Basically, the Favored Soul/Stormlord/Blackguard is all about buffing and going into melee. And Blackguard gives you Heavy Armor as well so don't waste a feat on it.
Also get Practiced Spellcaster (Favored Soul) when you get the Blackguard levels so your caster level will be a bit higher. You don't need more than 3-4 levels in Blackguard. Practiced Spellcaster requires about 4 Spellcraft though.
For races, Aasimar or Humans are probably the best.
Don't bother with crafting, Sand and the other NPCs can do it for you.