Trying to learn a little more science here; What is the benefit of changing Venus' spin?
At the time I wrote about Project Aphrodite, it seemed reasonable that a faster spin would help even out Venus's post-terraforming day/night temperatures and give a more normal day-night cycle to colonists. It didn't seem reasonable that 120 days of sunlight would produce survivable temperatures, given contemporary studies on tidally-locked planets around red dwarf stars. Further...
Still that seems easier to solve with the giant solar mirrors than going to the effort of changing the spin.
...mirrors were vulnerable to failure. Natural planetary spin couldn't be collapsed by hackers or, say, Amaris hoping to incinerate SLDF fleets.
However, the sheer rapidity of Project Aphrodite (and Lowell) meant that both were accomplished with brute force and massive ignorance. Venus would continue to suffer from an extremely hot crust, which was harder to cool than a stripped-away atmosphere. Solar illumination levels remained challenging. Solar mirrors had to remain in use to battle the two heat sources while the Terran Alliance (and later Hegemony) throttled back on terraforming efforts because much better planets were available just a hop, skip, and Kearny-Fuchida jump away.
Subsequently, improving exoplanet modeling has shown my theory about Venus needing a fast rotation was off-base. In fact, an Earth-like Venus stays globally coolest with very slow rotations
as stated in this long study.
Do humans have a problem living on a planet that has such a long year, or was it mission creep of what the Star League teraformers could do so they did it?
It was the Terran Alliance that spun up Venus. It seemed to make sense in the 21st-22nd century, when vast fortunes and vaster automated, almost von Neumann-like industries made world shaping possible. Smarter, more nuanced terraforming approaches seemed unnecessary.
Speaking of that are grav decks on ships/stations standardized to spin one way? Or does it not matter which direction a grav deck spins for generating artificial gravity?
Ships with more than one grav deck will typically have them spin in opposite directions (clockwise vs counterclockwise) to balance gyroscopic forces. Centripetal force doesn't care about the direction, just the velocity and radius of the spin.
Speaking of planets spinning we always think of planets spinning on an East/West axis with the poles at top and bottom. Could there be a planet where the planet rotates North/South with the poles rotating instead of being static?
By the definition of rotational poles that's not possible. Rotational poles are where the axis of rotation of emerges from the planet. If you took Earth, halted current rotation, and then started flipping it old north pole over old south pole along, say, the prime meridian, the new north and south poles would be defined at 90 degrees east and 90 west longitude at the equator because that's where the new rotational axis would be,.
There have been some extremely tilted planets in BattleTech, like Uranus and Inglesmond.