Talk to a partner. I can't speak to rumours of EOS or anything - I haven't heard anything.
Officelinx is the go forward platform eventually - that much is true.
Talk to a partner about your licenses and map out a few scenarios.
If you're Aura Core or on Suite Licensing, then that license for a user includes various entitlements - presence, chat, and voicemail.
Even if they were going to replace AAM with Officelinx tomorrow, there'd be a path to get there.
Even if you're right about AAM being EOS in 6 months - which I personally don't think is the case - it'll be supported for years to come. If there's any truth to that rumour, I might expect a roadmap announcement in 6 months to say it would go EOS in a year or 3's time with full EOL at a much later date.
Even then, AAM doesn't support O365 for full integration like "read in my outlook = lamp off, unread in my outlook = lamp on" but it does support just fire and forget to O365, so it can work just fine even if not the most elegant. Personally, I figure either you're a phone-only user to check voicemail or a email box only user anyway and don't really care about or need both to be totally integrated.
I don't see AAM going away anytime soon

Not at least until Officelinx gets rid of the Windows dependency and it gets a spin to be deployed in AAM mode that just lets you seamlessly upgrade to it like AAM6-->AAM7.