Yes, you can take the probability that they will halt given a random input. This is analogous to the case of a universal Turing machine, since the way we ask it to simulate a random Turing machine is by giving it a random input string.
Yes, you can take the probability that they will halt given a random input. This is analogous to the case of a universal Turing machine, since the way we ask it to simulate a random Turing machine is by giving it a random input string.