They don't put it all in one place to make it easy for you, unfortunately. :/
The best place to find companion stats and abilities is on the Companions page (you will want to hit the box at the top of the screen that says "show all" to see the ones you don't own at the moment). When you click a companion from here, a page will open that has more information available about its abilities. Everything has a passive, auto-attack and special ability. Companions with passives like Abnormal Speed (doubly so if they have Intercept for their special ability) are generally the best all-rounders for the front line, but some of the "tank" style companions can still get you wins if you build your backline to compensate.
The place to find your wolves' synergies are on the bottom of their pages. Stats for wolves and companions are all static based on level and breed, so any individuals of the same species and level are interchangeable.
To see Synergy information when team building, the place you'll most likely be to see that info first is on the Campaign page itself. In the lower right, under your list of party members, you can see the synergies you are currently filling. HERE you can hover over the synergy symbols to see their names and what each bubble/breakpoint does, so you can get a better idea if you want to aim for one particular synergy breakpoint or another. Why you can't just hover over a synergy bubble and at least get its name anywhere else on the site those symbols appear is a mystery to me, but it is what it is.
For campaign, a favorite team composition for a lot of folks is putting two Kits up front, and a Dire in the back alongside two companions. That will easily get through all of your campaign needs, as well as grinding for bones and materials later if that's something you choose to do. With the right companions-- and at max level-- that team also VERY easily kills bosses in the later areas.
Other people like stacking companions with "Pack Mentality" as their passives, as they will all buff each other's attacks based on how many others with that passive are also in the party. This is also very powerful, but it's a glass-cannon style build that works best when they are all already max level, a little less so if you are brand new and have everyone at level 1.