No, Chrome does not support this feature on iOS (https://support.google.com/chrome/answer/2364824?hl=en&co=GE...). iOS' WebKit limits this to only one permanent profile and one ephemeral profile. You can technically have multiple profiles in the iPad - that is, if you're a school, and that's really more of a OS-wide user account thing. (G did a hack over this by rewriting that profile when switching profiles - but it's not truly a multitask thing, and violates Apple Developer Guidelines).
> better spell checking (everything over Firefox)
No, and for more sensible reasons. Users do expect consistent spell checking because they use the keyboard to do that. Regardless, if you want to implement spell checking in-browser, that's impossible. If you want to do it outside of Safari, go ahead - it's just not integrated to those Apple things (more of a dedicated Grammarly interface rather than desktop spell checking).