They came to kRO Renewal, so I don't see why they wouldn't come to iRO Renewal eventually.
As for how pay to win it will be, kRO Zero is theoretically pretty not. You get your VIP packages for bonus exp and drop rate, but beyond that the cash shop is mostly just cosmetic and convenience stuff. Even things like Enriched/HD Ores and maybe even Blacksmith's Blessings are craftable in-game rather than obtained from the cash shop, if my research has panned out correctly.
There does seem to be some sort of paid currency thing similar to Silvervine for RE:Start, though I'm not entirely sure what it's used for. They say you can get it in game too, but they said that about SIlvervine as well, and we know how that turned out. The only things I've seen it used for so far are resetting Enchants on gear, but those gears also had methods to reset enchants with zeny/in-game items instead too.