I think you have to extend MediatorMap and set _active value to false ( then it will not set listeners like ADDED_TO_STAGE and REMOVED_FROM_STAGE ). They take very much of the performance. Then you map views as usual with autoCreate and autoRemove set to false (in fact it doesn't matter if you set _active to false). Anyway. To create a mediator you need to inject mediatorMap and use mediatorMap.createMediator(viewInstance). That's all.
Latest version of Robotlegs is missing _active field. Now I remember @jhooks and @darscan discussing about that field. So you just need to remove the usage of that field manually. Now Robotlegs has only enabled field which means the same (that's why _active was removed.) I'll try to fork LazyMediator from @darscan, push changes and ask @darscan to merge branches from me.