If there is no signed message available then .025 is too high for starting bid specially on potential FM account
not necessarily, if there is no posted address to sign from, the risk of the previous owner retrieving the account vanishes, making the account safe to purchase
not really safe, he could pretend that there is no address posted so he cant provide a signed message but it is possible that he posted an address before and now it is quoted by some user and he deleted it, by that he can be safe from claiming it back saying the hacker deleted the address posted. it is still much safe if there will be a signed message provided