I think all of these depend on the player, their assumptions, and preferences. For some, it will be good to have the additional information, for others, it won't matter.
1) Costume hints, yes, even if the answer is "average person in modern western society". If you want to allow player creativity, you could phrase them as "one idea, feel free to find your own".
2) Environment vs social. I think this varies greatly based on players as some are not particularly interested in environmental interactions, while others are intently so. I think it is most important to tell your players prior to signing up(via the game description) what it is you are running. For example, you could say "Oz is a theater style larp primarily focusing on player social interactions mixed with some environment interactions."
(One could argue that for a good run, it is equally important that a game description push away players who would not enjoy it as well as entice those who would)
3) I have seen extra information on badges used in many ways, though usually they are codes that should be ignored if the player doesn't have a sheet which explains that they should know it. In Oz for example, it would be unfair meta-gaming for those without the skill to be looking around for the *, and figuring out what it means. They shouldn't be seeing that because they don't have the skill. So I think in any case where there is information on the badge which is not obvious(like name, age, or visual description) most players assume that such a thing is going on, and fairly ignore it. I have seen many games where badges have character specific numbers on them which function similarly to the *, to trigger contingencies, or allow people to look up special skills. Thus, if you want to put non-obvious things on name badges, I think it is best to state in the rules what the meaning is.
Depends on the player, but yes...
1) Costume hints, yes, even if the answer is "average person in modern western society". If you want to allow player creativity, you could phrase them as "one idea, feel free to find your own".
2) Environment vs social. I think this varies greatly based on players as some are not particularly interested in environmental interactions, while others are intently so. I think it is most important to tell your players prior to signing up(via the game description) what it is you are running. For example, you could say "Oz is a theater style larp primarily focusing on player social interactions mixed with some environment interactions."
(One could argue that for a good run, it is equally important that a game description push away players who would not enjoy it as well as entice those who would)
3) I have seen extra information on badges used in many ways, though usually they are codes that should be ignored if the player doesn't have a sheet which explains that they should know it. In Oz for example, it would be unfair meta-gaming for those without the skill to be looking around for the *, and figuring out what it means. They shouldn't be seeing that because they don't have the skill. So I think in any case where there is information on the badge which is not obvious(like name, age, or visual description) most players assume that such a thing is going on, and fairly ignore it. I have seen many games where badges have character specific numbers on them which function similarly to the *, to trigger contingencies, or allow people to look up special skills. Thus, if you want to put non-obvious things on name badges, I think it is best to state in the rules what the meaning is.