I am in similar situation; have decided to put three individual pendants over long counter containing sink in middle and two more over a peninsula parallel to it 6.5 feet away. I didn't consider anything but matching ones, very small and simple, with a goal of having bold pattern on the window treatments that they will be hanging in front of. I found a few photos in books that showed multiple pendants and generally they used same model for the whole set but some varied in color of the globe of glass or used a diff. shape or scale of globe. Except when a pendant was more like a chandelier or whatever over a table; then it didn't have to have a relationship to the sink or island. Is there a reason as to why you don't want your pendants to match? Otherwise, standard practice seems to be to use a variant of one style on the other, such as a double-globe pendant on island and single globe matching one in another position. Same manufacturer and same finish, but sometimes with some kind of variation. I've been fighting the in-ceiling lights trend for task lighting, which I find to dissipate light instead of focusing it and which I cannot use in my ceiling-attic situation. What's your reason for pendants?

What's the wattage of the mosaic mini pendant? I would think using the light that mimics your vent hood would probably look okay if the sink isn't too close to the peninsula, assuming the wattage is high enough of course. The only concern I would have is a pendant over me instead of over the sink area; might not give appropriate light. Is the vent working? If not, could you take it out? Or maybe doing two smaller recessed lights on either side of that vent (depending how big it is across your sink area) would work better; then you would have the light properly over the sink? Hope those thoughts are of some help...

The rule of thumb is to place pendant lights @30-36" apart center to center. depending on the scale and proportion of the island. It would also depend on the size of the pendants. It is not clear where and if there is seating but at first glance, I would not put one over the sink. Is it too late to add any recessed lights?

I would not do a pendant in this kitchen, you wont get the impact because you can only do one and it cannot be large or it would look out of place over the counter top. another factor is your ceiling height, which I assume to be 8ft, this means a large pendant really wont work as you will not get much cord drop. I know you are looking for pretty here, I get that, but this room will change a lot once the wall goes back in and the counter is placed. if i was you I would have them center an electrical box where you want the pendant on the idea that they can come back in and change it to a remodel pot if you decide against it.