buyout focused vs contracted/yielding infrastructure?

Depends largely on the shop. What shop/what focus/what level?

Some are more buyout focused, some are more focused on contracted/yielding infrastructure with lower returns. If you're going for a pre-mba associate role, the buyout shops will give you an LBO model as part of the interview, the core shops will give you an LBO model or an infrastructure asset model.

Expect a few questions about the investment case i.e. risks, value drivers, upside, competition for an infrastructure asset you have looked at or would look at in the infrastructure space- again largely depends on the shop's specific strategy.