1. The Ilford recommendation is to those who have established development time based on intermittent agitation when moving to rotary processing with continuous agitation. For its B&W films, Ilford recommends no pre-soak.
2. The idea that a pre-soak will reduce airbells when loading the following developer is based, I suppose, on the assumption that an airbell is more likely to be left between film edge and spiral reel flange if the reel is dry, and less so if the reel and film are wet. I doubt that there is any objective study of that as fact. Moreover, it's practical nonsense, in that an airbell can be dislodged with a simple rap of tank on table, so where is there any logic in using a pre-wash for that? It's a solution looking for a problem.