The Ogre Bodyguard is one of my favourite hired swords so I use him allot and would always recommend him for mid to late campaigns ^^
In terms of equipment, sword + mace is pretty much the best imo, just makes sure to allocate one hit with the sword and the rest with your mace to ensure max use of the stunning bonus.
What I would say though in terms of strategy is to beware putting all your eggs in one basket. If I was playing against somebody who put their Vamp and Ogre in the one "group" as such, I would simply focus all my ranged attacks etc against them (large target makes this even worse for you) and simply take them down with concentrated fire.
Were I in your position, I would separate them and force the enemy to split their fire and forces, this way your vamp is technically being given extra protection from ranged attacks by the ogre's presence, but you also have the ability to use their superior movement to execute flanking/pincer movements or capture objectives, while your slower units can make their way to the objectives...but that's just my experience and depends on the opposing warbands + scenarios etc ^^'
If you are looking for some alternative protection for your Vamp, why not get a direwolf or two? they are fast enough not to slow down your Vamp too much and have great stats to boot!
One more thing I would recommend is trying to rig your exploration scores (tarot cards, wyrdstone pendulums etc anything to let you re-roll or adjust the results). Aim to get a triple 6 so you can get your Ogre to join up without the hire fee, saves you 80gold and trust me, if he dies one or two games after being hired (which is very possible with mid-high level enemy heroes) you will thank me for it ^^