Dealing with SoB? easy, use cards that have SoB ability like rescue's Kerry, Lea, or Sledg with his protection, Montana has Edd, he does good against Nightmare and Piranas... Noemi is great... it is not bad to have 5* in elo, but if You put 5*, You have to put a couple of 2*/3* also... 4/4 split is usually best, but sometimes it is wise to use 5/3, when we want to have 1 clans bonus more often, and the 3 cards of other clan can be played without their bonus (I use 5/3 split in decks with Sentinel Copper, Melvin, Lehane)... Leaders sometimes are the key in strategic playing, but building and playing a deck around Leader needs a little experience and good deck idea... lets say Ambre + Glorg, Oshitsune, Caelus? simple idea, devastating power, but if You put Caelus and Ambre in 1 deck, You have only 15* for the 6 remaining cards, wich is pretty painfull... pusycats/Jungo is good combo, especially with Sylth or well played Nyema, but playing this kind of deck requies experience, I dont advise using it until You get a hang of the game... to start with elo, I suggest using SoB or SoA clan bonus, or Rescue, they are very strong for beginers

SoB clans and GHEIST are both very expensive, and the low-end cards are flat out terrible (unlike Montana, where Riccado can actually win)

Mmm the problem you have is that Montana rely on their bonus, so that whenever SoB pops up, they usually don't take it well. (Hence why Edd is such a great card).
You mean Jeyn or Noemi right?
Noemi is 3*, so if you need any extra space go with her. (Sorry, not really expert on Pussycats)
Using 5* or 4* depends on your deck. Montana has the 2*s to definitely use them, but their 4*s are more reliable than 5*s. Also think about it this way: What's the WORST draw you can get from your deck? Always think about that too.
Leaders are not overrated. Unless you're using Rescue (And even then you might make a case for Hugo), Leaders always help. And really. you think it's playing man down? Most leaders have at least 7 Power, and their abilities CAN'T be stopped. (think about their bonus as Protection: Ability). Besides, Leaders help take down a clan's largest weakness.

I see you're a Pussycats fan? Well Jungo plays well with Pussycats. They have a great DR with Pegh, 2 Poisons (though one is banned nearly every week), and many cards whose abilities increase your life + the bonus.
Now Pussycats and Montana, i don't know. There isn't much synergy between the two clans IMO, but who knows? Maybe the DR in Pussycats is enough to overcome the low damage on both ends.

And yes it's true. Montana lacks a good SoA/SoB. Though that never stops a Hugo-Montana deck from being played nearly every ELO week.