So, if you really want to go Ghost Fleet, that's already severely limiting. If you're also excluding battle engine casters, that pushes you to a few specific choices.
Deneghra 1 is great at letting the flimsy Revenants hit above their weight class. The original reason the theme got nerfed into mostly losing their second initials, which is a big reason why it sees very little play these days. She has access to Ghost Walk so she can help the list navigate terrain.
Asphyxious 1 is similar to Deneghra, but doesn't have a hit fixer.
Terminus is not my favorite because he does very little for their output, but he does give a whole bunch of them Tough, which stacks nicely with their natural recursion to make them very difficult to remove (for good). He also appreciates having a never ending supply of Sacrificial Pawns.
Goreshade 3 likes having the Incorporeal models available that can get into annoying places to use his feat on. The Riflemen also help with his assassination potential and Mockery of Life is an extra recursion element in case some of your pirates don't make it back. If your opponent has no way to Remove From Play, then the army will be at full force most of the time.
Sorry, but every single Ghost Fleet list, in my opinion, should start with 3 minimum units of Revenant Crew of the Atramentous with max Riflemen, though you could get away with only 2 at 35 points. This maximizes your theme benefit of the +1 to Deathbound. The one solo you always want is Rengrave, because he's one of the few models that actually hits hard and is almost impossible to kill because he can let the other pirates die for him. The Hellslinger Phantom is a very strong choice, simply because he's good and Agrimony is a great utility solo, mostly for making rough terrain, negating tough and providing Tactician.
Seeing as your friend is interested in Goreshade, I guess he will go the Goreshade 3 route, which is a bit of a shame as he actually really likes having a Kraken, for the shooting output as well as being a great target for Infernal Machine.
At 35:
conflictchamber.com/?c4200z_-1VdTkA19192D2k2kkq203g203gCryx
[Theme] The Ghost Fleet
[Goreshade 3] Goreshade, Lord of Ruin [+27]
- Barathrum [15]
- Deathripper [6]
- Deathripper [6]
Captain Rengrave [5]
Machine Wraith [2]
Machine Wraith [2]
Misery Cage [2]
Revenant Crew of the Atramentous (min) [9]
- Revenant Crew Rifleman (3) [0(6)]
Revenant Crew of the Atramentous (min) [9]
- Revenant Crew Rifleman (3) [6]
For 50 points I might go for something like this:
conflictchamber.com/?c4200O_-1VdTkA19192DhC2k2kkq203g203g203gCryx
[Theme] The Ghost Fleet
[Goreshade 3] Goreshade, Lord of Ruin [+27]
- Barathrum [15]
- Deathripper [6]
- Deathripper [6]
Captain Rengrave [5]
Hellslinger Phantom [0(7)]
Machine Wraith [2]
Machine Wraith [2]
Misery Cage [2]
Revenant Crew of the Atramentous (min) [9]
- Revenant Crew Rifleman (3) [0(6)]
Revenant Crew of the Atramentous (min) [9]
- Revenant Crew Rifleman (3) [6]
Revenant Crew of the Atramentous (min) [9]
- Revenant Crew Rifleman (3) [6]
Barathrum and the Deathrippers are staples within Cryx and your friend will not regret getting them, even though I would squeeze in a Kraken instead at 75. Barathrum is an excellent target for Infernal Machine, as it makes him faster and more accurate against Warrior models. With his spell list, you could get away with only having one arc node, because you only really need it for the assassination, but like I said they're staples and it's not worth putting something else in the list as they are sold in pairs anyway.
The Revenants themselves are just there to never die, while having the rifles take pot shots with their Ghost Shot and/or Combine Ranged Attack abilities. The Misery Cage is always great to get some extra focus for your caster and the Machine Wraiths can get into annoying places with Scything Touch or for the feat. Rengrave and the Hellslinger Phantom are both super solos in their own right and they won't disappoint. The former can hit very hard, as one of the few models in the list while the latter will be tearing through infantry.
Most Ghost Fleet lists play in a similar way. You only have a few models to deal with hard targets in a single round, so the rest gets gummed up by expendable pirates, possibly chipping away at them over multiple turns. They're very inaccurate at range, but the list is theoretically a gunline, so with casters that have a DEF debuff, it can really pull a number on other infantry spam lists. The main goal is to keep your caster alive while not letting your army be destroyed (completely). You then either win on scenario, on clock, or on assassination, whichever presents itself first.
Be very careful not to use the Leader models! Deathbound is worded so that returned models must be within 3" of the Leader model, which means if you lose it to RFP, or by losing all the Grunts so none of them can be promoted, you effectively lose the ability. This is because Leader is a specific model; having a Unit Commander, which is just the model giving orders, is not enough to satisfy the requirement. This means that you have to identify RFP threats to your leader, such as opposing Hellfire spells and stay away from them. This is also why most players will keep a single Grunt far away behind the unit, so that it can always be promoted to if the rest of the unit dies and start replenishing. Note that the Riflemen can not be promoted to the Leader model, as they are not Grunts.
At 75, you could probably do something like this:
conflictchamber.com/?c4201b_-1VdT19c3jA2DhCkq2b203g203g203gCryx
[Theme] The Ghost Fleet
[Goreshade 3] Goreshade, Lord of Ruin [+27]
- Deathripper [6]
- Kraken [35]
Agrimony, Crone of the Dying Strands [4]
Captain Rengrave [5]
Hellslinger Phantom [0(7)]
Misery Cage [2]
Blackbane's Ghost Raiders (max) [17]
Revenant Crew of the Atramentous (min) [9]
- Revenant Crew Rifleman (3) [0(6)]
Revenant Crew of the Atramentous (min) [9]
- Revenant Crew Rifleman (3) [0(6)]
Revenant Crew of the Atramentous (min) [9]
- Revenant Crew Rifleman (3) [6]
Alternatively, you could take just a minimum unit of Ghost Raiders and do something else with the last 6 points. Note that here, the Ghost Raiders will be your main targets for the feat and/or Scything Touch.
