Well technically there is no real "need" to dual cast draemora lords. You can just cast one and then the next and they'll do the fighting. You can use a shield if you do so - which will make it easier to max out resistances and give you additional defense. On the other hand:
- If you're playing 1.2 patch Resistances DO NOT WORK. So at the moment there isn't really a point in getting them.
- In Order to get soul gems: Complete the Winterholt questline. The "free to take" soul gems will be restocked after a couple of days. But once you learn Banish you can easily buy any filled and empty petty, lesser and even common gems and you will still end up making money.
- If playing "conjurer style" there is not really a lot of need to max out weapon skills or improve stamina. You might want to get the "weightless heavy armor" talent though, so you won't be penalized when sneaking. Also you don't need "high end smithing" gear when playing a conjurer - because you will not be hit a lot. (I killed 5 of the Dragon Priests as a Level 1 Conjurer on Master with 100 life - conjure Lord, run, hide...

That being said Hitpoints is still the way to go when leveling up. You don't need magica (and should NOT get magica reduction/regeneration) skills, you don't need stamina - but HP will help you when taking the occasional dragon breath.
- If you play conjurer plus use a weapon things look different. In this case you should max out smithing, enchanting and alchemy. Though getting high resistances will be somewhat difficult because you might want to enchant your ring and amulet with +weapon damage/fortify conjuration which will limit the slots for resistance enchants (once those are working again, ofc) plus - you will want to max out the weapon of your choice and get the relevant perks.
- If you use a Melee Follower, their efficiency will heavily depend on gear, too. Strongest overall being sword/shield who can easily tank Dragons, Giants and Mammoths with good gear, even on Master Difficulty.
My advice would be: Level up Enchanting and play pure Conjurer Style. You can get Silent casting from the illusion school but the rest of that school is not really worth a lot, since most tough opponents will be immune. Same for alteration. I played Archer/maxed Illiusion @L65 atm but rarely ever use even the Illusion Ultimate spells.
Priorities: Get 70(100) Conjuration and the Draemora Lord spell (go up the left side of the tree), get 100 Enchanting and invest 8 Points in the relevant perks.