I have around 9000 crystals, which is very good for X30 in costumes.
Should I do it in this month, targeting Lianna and Vivica (they are featured) or better wait to next month with all remaining costumes released?
Then I will have less chances on Lianna and Vivica, but certainly will get a bunch of new 3* and 4*.
And Reuben is better as HoTM than Zulag.
Next month HOTM is Glenda. She anyways is by far better, to me at least, than Zulag.
It depends on your needs. With such amount of pulls you have high chances to pull a featured hero. But if you want to hold on , next costumes could be added in November. There are some really good ones
Not that the difference in odds to get a specific hero is huge if you wait in either scenario, let’s be honest, most likely you won’t get what you want 
I’d wait for the sake of new costumes and HotM, which you probably won’t get anyway (Murphy’s law says that you’ll get 2 hotms you don’t want if you pull now, and none if you wait for the one you want)
There is an question - 30pull now to try to chase Lianna and Vivica, or wait till November and do 30-pull there?
I do not need Glenda, I have very good blue roster
(C.Magni, Vela, Master Lepus, Fenrir, Rafaelle, Isarnia, C.Magni), first 2 are leveled, 3rd wait his scopes.
If you dont need Glenda it has no sense waiting to november Unless you want to chase new costumes, i dont know if they will be added next month anyways, i assume they will.
If what you really need is a green sniper, its clever to pull now that Lianna is featured
The Tittle: Lianna VS Marjana
I think I will wait for Marjana 
Remember that the guess costume featured is not yet fixed though.
My best green hitter now is Caedmon)
I forced to run 3 healers in my green war team(( I really need some damage.
And Almur and Lianna is a good pair)))
Maybe you want to try the portal with the spare free coins? Maybe buy the cheapest offers and then decide if going for a x10 or a x30 pull.
As i said, im in a similar situation that you with greens, and Lianna would be the best addition. The only thing stopping me to pull now would be the new costumes, in any case, depends on your interest in them
But when C.Marjana will be released, I will certainly want her (along with Leonidas, Thorne and Obakan))).
Lianna and Vivica is only one 5* which was not be featured in second cycle. So, they will be this month.
I would hold out for the new costume release, A lot of potentially good costumes in there and less chances of duplicates also, given all the new additions.
both are best s1 heroes tough CHOICE… if you can spend xtra getting both of them will have no regret!!