Yes, at JFK the lounge is as described above, terminal 8, 3rd floor.
Yes, at HEL you will have access to any AY lounge! I cannot remember the names (i.e. Fresh Lounge), but if it's in 2nd floor, it's in "shengen"area and not good for you. If you're flying HEL-JFK non-stop, you'll be leaving from "non-shengen" area (likely gate 31/32) and there are two lounges available. One is a "Long Haul/Platinum" lounge with airfield view(the best in HEL) and the other one is just a regular business lounge.
Have a great trip!