I want to chime in and say a few things quick because it's clear some people don't understand a few things. The reason these are being brought up as 'rules' is because if they are recommendations we can't by the site rules actually stop someone from making a character like this. In other words, there is no grounds to tell someone brand new to the site they can't make Godzilla, or some 10 year old soldier. If we want to be able to filter through people who we think can make these characters -responsibly- then it has to be a rule that you can't unless you get special permission. (I do think that if this rule comes into play the ability to get permission to bypass these on occasion for players who have shown to have a good grasp of the feel of SARP is a good idea)
As for the actual rules:
The first one is reasonable size not height, so I'm sure there are some things we can work with. I admit I don't know much about the Tsumi, but the Separa fit through doors, even if they are super long they can generally move about a standard building with no problems, even if it is uncomfortable for them, so they are 'reasonable'. I feel like the Tsumi could probably get around in a standard build, just would require uncomfortable movement?
As for adult characters if this does go in, firstly we need to make the fact that a YE year is shorter than an IRL way more clear. We also need to make it clear that ages on the wiki are to be considered in YE unless clearly stated otherwise. But also 'adulthood' is different for each species, and as long as that is maintained this is a reasonable rule. Remember this is to be a rule with the ability to get special permission to go out side of it. But we do not want to allow people to flood the site with characters that are not adults. No it hasn't happened yet, but if we wait for it to happen to make it a rule then that's just bad management, and it would be hard to fairly tell the flood of people doing it that they can't.
As for the Pre-YE rule...hmm personally this is a bit of a hard one. I totally get why it's a thing. Like the actual problem we have because of this will still happen in other ways even if this one does become a rule. (At least in my opinion) But there is for sure difficulties that come about being around before documented times, I didn't have it too bad cause the character I made was only BYE6 so nothing really happened in her history before we got to documented stuff. So I would say go with it, but recommend changing it to "No characters before documented times" because some factions do have a history that is documented before YE, so if they're a species from that faction it could be okay cause they could still write about what they did with reference points.