Skipping comments on the early Restless monsters for the moment, mostly because Frosty said everything I wanted to say. I'll comment on the newest ones instead.
Spirit Banisher: Yay, ghost-banishing tricks! Unfortunately, Atk of 1700 puts it well out of recruiter range, which is a pity for poor Shining Angel, who still needs a worthwhile target besides D.D. Warrior Lady.
Spirit Firefly: Unfortunately, use of this monster with Spirit Warder is kind of... I dunno, counter-productive? Since the restless monster is destroyed, then comes back, and then is still able to attack if I'm not mistaken owing to prior rulings on cards such as Giant Rat or Mystic Tomato. So in the end, you're ditching two cards per Restless monster.
Abandoned Bride: Quick burn to your opponent if there aren't Restless monsters in the graveyard already, and a way to pull multiple Restless monsters out. Nice.
Disgraced Emperor: And now we have the king of the Restless. Unfortunately, he suffers from "too quick, too little" syndrome- not enough burn per destroyed card, especially considering the trend of commiting as little as possible to the field until you make the final push, and afterwards he becomes a 2600 Atk fighter for your opponent for free. AND he's eight-star, so you can't use him yourself.
Starving Ghoul: Screwing with graveyards, yay! Unfortunately, he's a bit... well, let's just say that the Parasite Demons are pwning this set left and right because they go from the hand to the opponent's field. FROM THE HAND. Meaning that you get to transfer negative effects right away, as opposed to needing special support to do it.
Vindictive Soul: One card per turn? Would be harsh, if you had more to wall with than Spirit Warder, who goes through your hand incredibly quickly. Seriously, it's either miss bringing back a Restless monster and re-using its effect, or losing an additional card from your hand and losing them until you want to stop bringing back the dang Restless. Seriously, poor Warder.
Curse of Return: Once again- Counterproductive with Spirit Warder, but makes it possible to transfer Restless monsters.
Spirit Chain: Very good. It brings back the monster but, unlike poor firefly who brings it back during the battle phase, this brings it back during the end phase and makes things much easier for Spirit Warder.
Spirit's Possession: Demon Fusion Lite. The problem is the same thing that happens with Black Horn of Heaven: Cyber Dragon and Dark Armed Dragon are feasible targets, and possibly Dark Grepher, but that's about it. Yeah, problematic.