You have three very different yo-yos as your main choices. All of them fall under the “Undersized” category. The shape is where they all differ the most. The 44 has a very round shape, the Half and Half has a flat-rimmed shape, and the Yuuksta has an H-Shape. If you want diversity, pick the Half and Half and then one of the YYF metals. Not only does the Half and Half have a different manufacturer, but it also is made out of a different material.
If you do decide to go that route, then the big choice is between the 44 and the Yuuksta. If you were thinking of getting a Genesis, before, then the Yuuksta may be a good choice since it has a similar shape and stability to that of a Genesis. The 44 is a bit more of a classic looking yo-yo. It’s a tad heavier and about the same size as the other two. Think about which one you would like better.
Of course, you don’t have to narrow the choice the same way I did for you. You can choose the two YYF metals if you want, or even something completely different. Ultimately, the choice is yours. When in doubt, just pick the two that look the coolest to you, or the one that looks like it plays the best. Pretty much all yo-yos are good these days, so in the end you win no matter what.