Each UE is assigned to a distinct eNodeB-sector. If RRHs are activated, they are part of this eNodeB-sector. The total received-power from all sector-antennas (including the RRH-antennas) is considered for the UE assignment. Therefore, there is no distinction between sector-assignment or RRH-assignment.
For your second question: Line-of-site is in general implicitly modeled by the channel-model and the shadow-fading (and their realisations). Please specify further what you mean by “how can we check if UEs has a direct line-of-site or NOT”.