Is their a console code to where I can respawn the solitude guards? I've tried finding it on http://elderscrolls.wikia.com/wiki/Console_NPC_Codes_%28Skyrim%29 and I couldn't find the code.

Note: They will not respawn after I've slaughtered them.

Havent tested myself but these should work to spawn Solitude guards:
2e1f0
6b340
853c4
a9621
10c068
1020a4
1007fa

Will these automatically change the title of the guards from Solitude guards to whatever team (imperial/stormcloak) you're on?

You'd have to test the codes out to see. For a video I was working on I had spawned more whiterun guards and stormcloaks during a battle and some spawned guards did adjust, others didnt. Hopefully it will be the same for Solitude guards.

I already finished the main civil war story as a stormcloak and when I used the codes the guy station at Solitude started attacking them. along with the Solitude guards that I've spawned. It seems as if they're programmed to function before the war, and not after. I've just re-spawned them again, and took off. I'll see if they changed their names from "Solitude guard" to "Stormcloak solider" as time goes by in the game.

An addition the following codes:
10c068
1020a4

has an appearance of imperial.