They never said why your ghost was looking for you for a long time.

Maybe it's before we died the first time. It's not like we remember anything.

Very unlikely, when our ghost found us he had to generate us new, shitty armor (hence the starting armor's description) meaning we were likely not wearing guardian armor when we died. Plus, it's to my understanding that ghost and guardians typically have a sort of "bond" with a certain guardian/guardian-corpse, hence why they can only revive their guardian and not other guardian, even guardians in the story such as that dude we come across who dies at the end of the Nightstalker mission (I'm assuming you know what I'm talking about, based on your pic). This is mostly from memory, so I'm not 100% certain on it. And just to further support my argument that it's a sequel, not a prequel, the Hive and Vex weren't really a threat before Destiny 1. Based on your Ghost's surprise at the presence of Hive on Earth and Vex on Venus, which suggests they mainly kept to their base-worlds before the events of Destiny 1. We also weren't at war with the Cabal before Destiny 1, and there have been many leaks suggesting the Cabal will be the main antagonist of Destiny 2, like the Vex were in 1. And I also recall there being a grimoire card that stated, since we pretty much -blam!-ed up all of their forces in our system, that the Cabal empire outside the system will have to focus more of their attention on us now, further suggesting the Cabal might come along and -blam!- shit up in Destiny 2.

Ya but our ghost didn't even know about vault of glass and the guardians went in there long long ago. Venus is full of ancient vex tech so they have been around. Maybe our ghost now wasn't around when you were alive and was sent out to find you because you were bad ass back in the day. Cabal not sure if thats legit. Not comfirmed yet. Cabal could have been the first to invade and then where pushed out to mars by fallen and hive.

I don't recall the ghost ever stating surprise at the existence of the vault of glass. But even so, it should be noted that the guardians which went in there before went in there so long ago that their existence was questioned. Hence why Ikora stated "He is real..." after that one guardian stated his name, as if satisfied by the confirmation of a legend. Also, Venus is full of ancient tech of course, but there's no telling how much of a hot-spot it's been for guardian patrols in the years just prior to Destiny 1. It should also be noted that your ghost was already aware of what a Vex was and is. So his surprise was only from their presence on Venus and since it's shown he does have information on your enemies (including where their bases are in our system, as shown from our ghost knowing that the hive came from our moon) it's likely that either Venus wasn't patrolled much by guardians lately, or the Vex were tucked away and hidden for quite some time, maybe leaving their architecture behind with no explanation from them. Also it's likely the leaks are legit, considering an actual Megabloks set had a description describing it as Shaxx standing off against Cabal "red guard" in the City. This is an actual, real set from their website and not some fake "I made something in Photoshop then took a photo with my phone" leak, so it's likely real and it also likely suggests the Cabal are invading the city. And again, we were completely neutral with the Cabal until we decided to jump in and shoot shit on Mars in Destiny 1, so the Cabal couldn't be the ones invading if it were a sequel.

Dude I'm out that's too much thinking for this guy.