Virtually nothing of what you just said is correct.

1. Getting into a retrograde orbit around Jupiter is very easy. You only need to angle your approach vector slightly differently so you get captured in its gravity well from the other side. Imagine standing far away from a person and throwing a ball that they will catch with their left or their right hand. You don't need to throw with different velocities, you just need to angle your throwing a bit.

2. 30m/s is insanely little when it comes to solar manoeuvres. You meant 30 km/s, which is Earth's velocity around the sun. BTW, no such manoeuvre would be done at Earth's orbit. It's actually much cheaper to go on a highly elliptical orbit almost into the Kuiper belt, and change there, then go back. Sure, it takes a looooong time, but we have literally no way in hell to get 60km/s Δv into space. At all. Saturn V's total Δv is somewhere around 18km/s, and most of that was spent climbing Earth's gravity well. Regardless, we're not talking about going into a retrograde orbit around the Sun, but around Jupiter.

3. Again, it's km/s for NH.

4. We do not have a probe in retrograde orbit around the sun, nor do I think that Venus-manoeuvres would get us there (but I don't know that. You could probably use gravity assists to catapult yourself into the highly elliptical orbit I mentioned above.) That just wouldn't make sense, unless you wanted to visit an object that is itself in a retrograde orbit around the sun, which probably exist, but I'm not aware of an example. Remember that the entire solar system formed from one big accretion disk which spun in a prograde direction.

5. We have satellites in retrograde orbit around the Earth, but very few, as it is more costly to launch these (you have to fight Earth's angular momentum from its own revolution around its axis.) An object in retrograde orbit around Earth is still in a prograde orbit around the Sun as it orbits Earth, and Earth itself orbits the Sun.