LittleJo - they changed the process significantly from when we first went through it. There are no more nominations and all steps post-application and pre-invite is done through placement, including the interview.
"Under consideration" means that you are being considered for a specific spot in a specific job in a specific country along with others that have been selected to 'advance' to this stage. You will most likely get an interview (although that's not guaranteed) by placement, and then, if they select you, an invitation.
My understanding from placement is that they put more people under consideration than actually get invited, so to answer the original question, no, it's not guaranteed. IF you get an invite, it will be for that country; there's a chance (from stories I've heard, no specific info from PC itself), that if you are competitive for but don't get the invite, that you can be offered to switch to another country to be considered for.
P.S. - I just realized that this is a bit of an older question, but I already typed!