Are they going to taste different than the tinned/canned version?
White anchovies are marinated in a vinegar brine. They have a very different taste from 'brown' cured anchovies - much more fresh and delicate with a tang from the vinegar of course. Personally I love them, but I think you might find that their flavor will not hold up well on a traditional pizza. Would be better on a crostini or traditionally served with olives and capers. I think they would be great in a salad, but they wouldn't be appropriate for the traditional caesar dressing unless you are looking to incorporate the vinegary tang.
Yes, Give one a taste. They are much milder than the dark ones. You may decide to put them on the pizza, perhaps with some arugula or other greens, after taking it out of the oven.
Also look for tapas recipes with white anchovies.
When I use white anchovies, I leave them chubbier than the brown ones. They are very mild. The ones I buy are packed in oil, so it depends how yours are processed. I also like to serve a big bowl of Caesar salad and crisscross two of them on top. They are very pretty. I've never had them packed in a vinegar brine, so if yours are, I don't know what I would do with them except use them as part of a tapas plate.
They are delicious on crostini with a squirt of lemon. A very popular tapa in Spain. Best to use good italian anchovie for pizza or caesar - not the ones in the flat tin but the better quality ones usually in a glass jar imported from italy.
As the others have suggested, white anchovies are pretty delicate in flavor. If you use them on a pizza, be sure it's a white pizza, with perhaps some artichokes. I wouldn't use them in Caesar Salad.
Great in a grilled cheese sandwich. Switch olive for butter when cooking. Favorite midnight snack.