I don't think your memories, personality traits, etc. are what make you you. There are a few reasons.
First, I just take it as a given that we maintain personal identity through change--both physical and mental. This isn't something I can prove. It's just something I take as a given because I'm a common sense realist. Every day we acquire new memories and forget old ones, but we're still the same person. You go from being awake to being asleep to being awake again and never cease being the same person. You can be in a good mood one day and a bad mood the next day and still be the same person. You can have a change in personality due to alcohol or bad life experiences and still be the same person.
So I think there's more to what you are than your mental states. Your mental states are had by you but they are not the same thing as you.
Second, if it's possible to create a human body/brain and implant somebody else's memories and personality in it, then it's just as possible to implant false memories and personality. You could put information in an another person's head about events that never actually happened. Obviously if a person's memories are of a past that never actually happened, then the person who has those memories cannot be the same person as the person who actually experienced that past. That past didn't exist, after all, so neither did the person.
With that being the case, suppose you did the exact same thing--implanted memories into a human you just brought into existence--except this time the events in the memories actually happened. It would still be the case that the events did not happen to THIS person you have just created. It's no different than if the memories had been false. In both cases a person has memories of a past that didn't actually happen to them. It doesn't seem to make a difference whether the events took place or not. If memories are implanted in a person who just came into existence, then that person cannot be the same person the events of those memories happened to.
Third, if it's possible to copy one person's mental states into another person and have that new person be the same person, then it would be possible for one person to be in two different places at the same time. It would have to be possible for two people to be the same person.
But that is clearly not possible. According to the indiscernibility of identicals, if A and B are the same thing, then whatever is true of A is also true of B and vice versa. Also, if there's anything true of A that is not true of B or vice versa, then A and B are not the same thing.
So suppose there's a guy name Jim. Let's call him Jim1 because he's the original. Then you create a duplicate we'll call Jim2, and we'll implant all of Jim1's memories and personality traits into Jim2. From the moment Jim2 comes into being, they will begin to have diverse experiences. Not everything that happens to one will happen to the other, so their memories will begin to diverge. Since there will immediately be things true of one that are not true of the other, it's impossible for Jim1 and Jim2 to be the same person. Jim1 will have no first person access to Jim2's experiences, and Jim2 will have no first person access to Jim1's experiences, so it is impossible for them to be the same person.
So it's impossible for Jim2 to be the same person as Jim1 even if Jim2 was implanted with all of Jim1's memories and personality.
At least that's how I see it.