Divine Souls rule! My favorite Sorc subclass by far. I'm playing one in a Storm King's Thunder campaign atm (Lvl 5 DS Sorc, lvl 2 Hexblade Lock) and I really dig it. As for your specific questions:
1 For sure. "Divine power" gives a huge range of background potential. Personally me and my DM homebrewed the sublass into a more "Devil Soul" theme, the idea being that as a Tiefling he was created through fleshcrafting in the City of Dis. But wether the source of your power is good or evil that doesn't decide the allignement of your character ofcoarse, it only gives more story potential.
The only major change we made was that instead of a free level 1 cleric spell he got Sigil of Dis (lvl 1, bonus action, deal 1d4 fire damage to a target, it gains twice that amount + spellcasting mod in temp hitpoints) since he's more into reinforcing then healing. It also avoids whack-a-mole scenarios when people go down with multiple Word casters in the group, which undoubtedly strong I always find sorta cheesy. I'm also allowed to cast booming blade with reach on my whip (normally it's always a 5 ft cast range) but that's more of a hand wave.
2 I think that as a Sorc you will most often still find yourself to be the blaster, but with the cleric spell list you get some very clutch support tools on top. Some of the damage options at low levels are also better then what Sorc's get. Here are, I think, the most important ones: Healing Word/ Bless/ Guiding Bolt/ Spiritual Weapon/ Silence/ Revivify/ Spirit Guardians/ Death Ward/ Greater Restoration/ Raise Dead/ Heal/ Heroes Feast. It depands on the rest of your party, and a whole bunch of other factors, wether you are going to need those but they are definatly worth considering.
Favor of the Gods is also just incredibly good. Adding 2d4 to your most important saving throw of the day is invalueble and when used correctly will save your ass more then once.
3 Not really. To be fair though, Multiclassing with Warlock gave me a bunch more spell choices at low levels (and a lvl 1 slot on short rest), plus I got the magic initiate feat (familiar, booming blade, mending) @ level 1 in exchange for my tiefling spells + fire res. So that expanded esspecialy my cantrip list by a bunch.
When the class variant UA came out we (the bard and me) could also start changing 1 spell known per long rest. This is mostly used for story reasons (so I can switch to something like Speak with Dead, for example, get the story dump the DM is itching to unleash and switch back to fireball later) but also gives the option to switch to counterspell instead when you know you are going to face a mage. You are still not close to a wizard in felxibility but it defiantly helps. If your table plays 100% RAW then planning your spell choices carefully in advance (and fully utilize the rule that lets you switch one spell per level-up) is key. Guiding Bolt and Sleep are 2 prime examples of spells that rock from level 1-4 but loose a lot of steam after 5.
4 I went for Twin and Quicken. Twin-cast is esspecialy good at low levels with Guiding bolt (2x 4d6 damage and advantage on next attack) or Booming Blade with Shadowblade active. Twin Healing Word (or Sigil in my case) is also solid. Later on you can use it on a variaty of other things like Haste, Greater Invis, Heal, Finger of Death/ Dissintegrate ect.
Quicken is for that double eldritch blast nastyness. when you got a cantrip that good it's never bad to cast it as a bonus action when you need burst. It's also super usefull sometimes to be able to cast something as a BA and use dodge or so as a main action, esspecialy when concentrating.
5 I build him as a caster that can comfortably stand just behind the frontliners, when needed. As a Hexblade he gets medium armor + shield and martial weapons (whip for a reach weapon that isn't heavy) and with the Shield Spell, Mirror Image and Sigil for temp HP he is very durable.
But if i'm honost building him for melee is not optimal and requires some handwaving from your DM. As mentioned I can cast booming and green flame blade @ 10 yards with my whip, I can use my Hex Warrior feature on Shadowblade when instantly when it's cast and I dont have to worry about somatic components when I'm holding a shield + weapon (casting focus).
Some of that felt kind of OP at lower levels but very quickly evened out. With 2 levels in Warlock for agonising blast it's hard to even find reasons to get into melee tbh (unless you can get some good spirit guardians off). Take from that what you will, but my advice would be to build him as a primary blaster with good support options.
6 I think you can guess that answer ^_^ Let me know if you have any other questions!
