Well the elite plus passenger should get an extra 1 bag or +20kgs allowance.

If they check your baggage all the way through to the final destination then this should be no problem.

Then Lounge access is a maybe for contracted lounges. If you just show your elite plus membership they will not invite you in so you need to get an invitation from KLM upon checking in. Maybe you can ring them to ask before hand.

Upgrades.. I assume you mean complimentary/op-up?

Your chances will be very slim. They will upgrade their own elite members first before any sky-team elites. You will be higher ranking than those on Elite memberships from other airlines and non elite flying blue/delta members and non members.

Hence your best chance for upgrades is to fly CI as now your emerald member and that only happens maybe 3-8% of the time.

Seems CI has given out many Emeralds recently for status matching, quite generous considering i doubt i could get similar ranking for status matching with other airlines.