Hearthpwn

Bloodmage Thalnos is the Legendary for Rogues. He is used more than Van Cleef and irreplaceable on rogue decks. I think he's worth it and its more fun to play an "archetype" deck that's complete. If you love playing Rogue you will not regret crafting him. If you're really not sure and you dont have Dr. Balance better craft him instead.  When i was starting out I did craft top tier neutral legendaries like Rag, Sylvanas, Cairne(was staple on vanila) so that I can play them on every class. The gameplay experience went stale very fast because the playstyle is pretty much the same regardless of the class. It felt like I'm playing an arena deck.

Loatheb is often used on Oil rogue. "Standard" builds have them. He's good on locking down the enemy player and secure damage the next turn.

I would favor Alex because of her unique bcry effect but only if the decks that I'm going to use her with is "complete" or almost complete. Most of the decks that uses her are a bit expensive. Followed closely by Ysera and then Sneeds,  all cards feels similar for me and they're great on control decks.
Harrison has a very specific function, not a priority for me.
Barron Geddon was used on Control Warrior but not that common in the current metta.
I wouldn't craft Cairne, He's meh and there are cheaper and better alternatives like the Piloted Shredder/Sky Golem.
For me, I would rather start crafting class legendaries. Grommash, Tirion, Antonaidas and maybe Jaraxxus/Malganis (latter two, not must haves, but they are fun!). They just make any deck of that class better and more interesting to play.. I also crafted neutral rare/epics/legendaries when I was starting out and the game eventually became boring. Although I can use all of the class but playstyle is the same, it felt like I'm playing an arena deck, it lacked identity.

2 x Preparation will allow you to make good/competitive Rogue decks. It is pretty much a must have. But you might want to craft Bloodmage Thalnos if you still don't have it.

Same goes for Ancient of Lore A must have for every druid deck, If you want to play combo druid(cheaper and easier to craft compared to other drud deck) you need to craft Force of Nature.

Its hard to pick from your wishlist since most of the cards are important components on their respective decks. You can't go wrong in crafting any of those if you're going to use them on the correct deck.

It would all depend on what deck you would want to play. The legendarys you mentioned have specific uses and shines well when you build around them(except for harrison which is a tech card), they're not as good in an "incomplete" deck. It almost feels the same as crafting staple class legendaries (Grommash, Tirion and maybe Antonaidas) even though they are class cards they used in almost all deck type of that class. You pretty much have all of the staple neutral legendaries, I think now is the time to craft cards towards "completing" a deck you like.

I agree with MasterPenn not having Lightbombs means that you're playing a deck with an entirely different playstyle. IMO not sure if the adjustments helps because the deck is designed around Light Bomb.  Might be better if  you find a different Priest deck.

Core of this deck comes from savjz lightbomb priest, with small meta game changes.

Replacing Lightbombs would be really hard. If you really need board clear another option you can try Auchenai/Healing Circles but it requires more card slots and its a 2 card combo so its greately inferior to Lightbombs.  Auchenai's also has has synergy with Zombie Chows but its not significant on this deck. 

Having trouble against Warriors with this deck specially Control. Really hard to catch up when he has an established board. Pretty much denies the use of Flamewaker synergy when there's an Armorsmith and/or Acolyte around. Plus high armor makes it really hard to put pressure on him.

I think Loot Horder is better on this deck, He trades better than Thalnos, that 2 attack is very useful early on. You may replace him with Bloodmage thalnos but I'm not sure if it will make it better. The deck is a bit aggressive relies on efficient trades to control the tempo, whirlwind is often used to trigger combos and not for board wipe. I just feel like Bloodmage Thalnos + Whirlwind is more of a defensive and reactive move which is suited for control warrior playstyle.

Can't really find an effective  replacement for Bloodmage Thalnos. Awesome card for Oil Rogues, times where you need to play him just cycle cards is not rare. He also serves as a combo trigger and gives your spells damage boost. That's why he's a Legendary.

Can't really replace Loatheb because of his unique bcry effect. A well placed Loatheb prevents your board from being wiped and helps you snowball for the win.

Im not sure about this card.. If you use this on combo grim patron deck 2 mana whirlwind is a bit expensive and the 3 damage will clear your minions as well. Not sure if this works well with control warrior either since you pretty much want to turtle up and keep your hitpoints high.. 

ET is OP IMO, Yes he doesn't work well with aggro decks but leaving him on board for two or more turns is basically suicide.  Mana reduction is never irrelevent. He makes succeeding turns unpredictable, instances that will enable  a player to cast multiple minions/spell combination that is impossible to cast on the current turn he's on is not unlikelly. Even if his cost reduction effect is a bcry effect I think he'll still see play.