Hmm dont get it?
Chrome web store extensions works for me with iron, dragon, opera (with Chrome Extension for opera) without any problem at all.
Good! Then maybe you can explain to me how to get the extensions for Iron browser, because I find no way to take and install them. Never been a problem with Comodo Dragon or with Superbird browsers.
I since lost interest in Iron because of this, and have been using mostly Superbird and Comodo Dragon.
YOU cant always try Yandex!
IE 11 + included TPL (tracking protection list) with disconnect beta for IE at the moment is providing more protection then any current browser I used.
Couple that with adguard (recommend 4 people for 30min install to get 1year free licence) and enjoy the web protected private secure and fast !
Its working fine for me 
i download the extensions @ chrome store and simply install them…
I have no idea why that isnt working for you, maybe you should talk with the iron browser support team?