Could be also the protagonist Ryder a N7,like father Ryder?

If Cerberus can slap their logo onto everything why can't the Alliance do the same with N7?

Cerberus might have been evil and terribly written, but at least they understood the importance of brand recognition.

^ I know you were joking, but there actually was an N7 located on some of the helmets that Shepard could acquire.

I think that during development this part might've changed. It's clear We don't start as N7, given the default armour (with the Ai insignia), that reflects the colours of the new organization, like N7 did with the default armour.
I'm not sure we'll become one during the game, but we don't even know if this is the start of a new trilogy or a scandalone game.

When the N7 programme is in the Milky Way as are the people who put you on it I think it's unlikely. The folk in Andromeda aren't part of the Alliance any more, they are wholly separate, they might not have a military at all.

Uh, what about FemShep?

Okay, let me clarify some stuff:
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from wiki:

-What is N7:

N7 is a vocational code in the Systems Alliance military. The "N" designates special forces and the "7" refers to the highest level of proficiency. It applies to Alliance personnel who have graduated from the Interplanetary Combatives Training (ICT) program.

-What is the Systems Alliance:

The Systems Alliance is the representative body of Earth and all human colonies in Citadel space. Backed by Earth's most powerful nations, the Alliance has become humanity's military, exploratory, and economic spearhead. While the Alliance is relatively new to the galactic community, it has already made a name for itself, gaining humans an embassy on the Presidium. The Alliance is governed by a parliament based at Arcturus Station, which also serves as the Alliance's capital.
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That being said, i think there's no reason for N7 to exist in the new game as the main "force" or "institution", since it's a joint-venture from several races and it doesn't have to do with military in the first place, let alone with grades like 7.
So, they came up with the Andromeda Initiative, which makes much more sense.
Now, adressing the question about why the old character uses n7 symbol:

Hes supposedly the Ryder family's father, therefore he was graduated back on Earth , thus becoming an N7 character. He is seen on the trailer in Andromeda while using n7 armor, which means he makes the jorney there and he probably still uses this symbol in his armor because of what it meant for him and for humanity back on Earth and when they needed the alliance against the reapers.
Almost like a principle, a way of life, something he would teach his Ryder son and daughter to fight for, even though they wouldn't see what n7 really meant on it's golden days because they were probably born to late for that.

If i wer to guess, i'd say that Ryder father dies at the begginning of the game, probably on that very scene from the n7 2015 trailer, leaving his children as the "leading" people on the exploration mission, where he/she is going to reveal what really happened with Ryder father and who are those remnants.

I don't believe Bioware will make Bro/Sis Ryder a N7. There is already the father for that and there is also the reason brunobyof stated above.

Yeah Miranda was created from the Y chromosome of her father and a modified duplicate of the same chromosome. She is even infertile as consequence.
Sometimes i wonder if that would make her a transsexual.

well they are supposedly pathfinders, which is often a more specialised branch of special ops, but for someone as young as them to have qualified they would of been in training since very early childhood, especially given all the intel side story that's been released as well...

I rather suspect the whole arrival trailer will end up being the end of a 25 minute intro detailing how they left just as the reaper invasion was getting underway, that they barely escaped their base ahead of the swarm of invasion craft and as a consequence haven't got all the correct people because they filled the ships with whoever was handy and pushed off with little to no chance of success, got to a repositioned mass effect relay and shot out across open space towards Andromeda effectively side stepping the whole destruction of the relays problem being outside the blast zones.

then they arrived after only 300 years instead of a thousand years at normal FTL speeds (thanks to the increased speeds) without needing fuel tanks the size of the citadel per ship to get them there

and that daddy had only been at the staging area either as a favour to see his kids off or because he was leading the security team and ended up being stuck with them..... as t o the whole N7 on the armour stuff, you wear what's available in your size no, if that's what they found in the ship supply locker that's what he would put on regardless of training or qualifications /

Well the thought crossed my mind when I played ME2. Not that it botters me.

Hey,hey people...maybe I found something.I was replaying ME3 playthrough,I saved Ash...and for the first time in 4 years...i saw on her armour written S1..what does this mean?N7,S1?...and protagonist Ryder has G2 on the back of the armour.
I searched on google the G2,and I found this:
www.eur.army.mil/G2/
Maybe...the kinder Ryder...is not really an unexperienced in terms of combat.
And I also found this:
The designation G2 comes from the continental staff system, a form of military organization used by the United States and NATO countries.

A military staff is an organization that is not in the direct operational chain of command, but assists a commander in carrying out his responsibilities. The G2 is one of several elements in an Army command staff:
G1 - personnel
G2 - intelligence
G3 - operations
G4 - logistics
G5 - plans
G6 - communications
www.quora.com/Does-G-2-refer-specifically-to-U-S-Army-intelligence-or-to-all-military-intelligence-in-general

Yes, it's on the wrong side. It's bugged me since I saw it

Anyway, it is extremely unlikely Ryder will ever become an N7 operative, for one simple reason. Those designations come from 2 parts:

1. The letter denotes which branch of service someone is. "N" is the designation for Alliance Special Forces.
2. The number indicates one's combat proficiency, with 7 being the highest rated.

Since it seems unlikely that Ryder (junior) will be special forces and "Pathfinder" seems more like a scouting title, I very much doubt they will ever achieve the rank of N7. Any-other-letter-7, maybe

Edit:

Not really