1. What are their zodiac signs?
Krypton, Superman's home planet, is located in the Andromeda Galaxy. It stands to reason, then, that Superman wasn't born under the astrological influence of the Milky Way's planets and constellations. This creates a problem: what zodiac sign can we attribute to Superman? The only possible Andromedan exoplanet that we've so far managed to detect is PA-99-N2, which doesn't lend itself as readily to the astrological imagination as does a planet named after the Greco-Roman goddess of love. In the context of the DCU, of course, superheroes such as the Green Lanterns allegedly patrol the 3600 sectors of the universe, and presumably possess much more advanced knowledge than we do about the astrological makeup of Andromeda. However, until further information about the astrological traditions of Krypton can be salvaged from the Fortress of Solitude or from some other surviving Kryptonian archive, Kal-El's (and Kara Zor-El's) star sign will remain undisclosed on his Tinder profile.
In the meantime, Lois Lane, Lana Lang, Bruce Wayne, and any of Clark Kent's other romantic interests are encouraged to seek out some other method by which they can test their cosmically ordained compatibility with the Man of Steel.
It is worth noting that Kryptonians born on Earth are exempt from this particular conundrum, and can date as many astrology enthusiasts as they like.
2. On what date is it considered polite to mention that bestiality is technically illegal in the United States?
Although Kryptonians and humans have been proven to be genetically compatible to the extent that first-generation hybrids such as Kon-El and Jon-El have been produced between a Kryptonian and a human, it is unlikely that Kryptonians and Homo sapiens are the same species. This, then, puts any human romantic partner of a Kryptonian in a legal grey area: bestiality, or intercourse between humans and non-human animals, is outlawed in most developed countries.
It is worth nothing that the spirit of such laws in the United States (most known Kryptonians' country of citizenship) is to prevent animal cruelty; since the non-human actor cannot meaningfully consent to the relationship, bestial intercourse would be tantamount to rape. However, Kryptonians are, by most philosophical definitions of personhood, Kryptonian persons; unlike non-person animals, they are able to consent to intercourse. With the help of a good lawyer, any Kryptonian who finds themselves in legal trouble should be able to prove their case for not falling under the designation of 'non-human animal', possibly setting a landmark legal precedent in the process.
Which brings us back to the question of: on what date is it appropriate to mention to your date that you might, in the near future, together be contributing to the diversification of stare decisis? Could this be a heavier commitment than marriage? The bio features of most dating apps aren't equipped to host this kind of information, which is disappointing since it seems to be a much more important thing for potential dates to be tipped off about than, say, one's vice of choice after a long day at work.
3. Are they automatically anti-marriage?
It's a tricky question, but an important one in today's forward-thinking dating culture. If a Kryptonian marries a human and, as most of their species is wont to do, takes up the mantle of a superhero, the spouse is potentially liable to compensation claims that might be made against the Kryptonian for laying waste to, say, most of a major coastal city. For this reason, any Kryptonian venturing into the dating market might be compelled — due to their conscience or otherwise — to make it clear out of the gate that they are against any registration-at-the-courthouse, in-the-eyes-of-the-law kind of matrimony.
Alternatively, more and more Americans are getting pre-nups before marriage to protect their spouse from the clutches of the American debt collection system. Could this be an arrangement that Kryptonians might look into? Assuming that they maintained a good relationship with the lawyer that helped them sue against bestiality and win, it shouldn't be too difficult to draft an ironclad pre-nup that protects the human spouse from all charges of property damage that the Kryptonian might incur.
It is worth noting that if the Kryptonian's significant other is a member of the Wayne family, the charges are probably going to accrue to them anyway.