You mentioned you passed part 1. Is that the v5 exam?
The part 1 exam determines what version of EA cert you shall get.
Just to note that the EA6 upgrade is the same exam as EA6 part 1. So technically if you continue with parts 2&3 (get the v5 EA) then do the upgrade ... you will have both credentials
However, if you start afresh with v6 part 1, parts 2&3, you will just end up with v6.
From the money stand point, I doubt you want to waste it by doing the v5 part 1 exam in the past. Furthermore, the upgrade part can be done later. If v7 comes along you can do that too directly skipping v6.
About the validity issue, I guess it's still valid for some time.
Edit: Almost forgot, Oracle now needs mandatory training in order for candidates to "complete" the track. Hence without the training, Oracle would not say you are certified.