There should be no problem with the use of the ViaLight™ Plus Kit with immobilized antibodies. You can if you wish confirm this with your own experiment by conducting a control experiment as follows:

Coat triplicate wells of a 96 well plate with each antibody to be tested and detect the ATP by treating the wells as if they contained cells following the protocol contained in the kit. If you use the ViaLight HS kit add 100ul of NRR to each well and wait 5 min before adding 20ul of AMR. The difference between the RLUS from coated and uncoated wells will show if the antibody is contributing to the assay