Permethrin SFR 36.8% is labeled to be used in kennels and would be safe when used as directed on the product label. It is also safe to use as a flea/tick dip on dogs.
These products should not be mixed together. There is no valid reason to mix Onslaught and Permethrin SFR together. They are both synthetic pyrethroids so there would be nothing to gain by mixing these products together. Making a pesticide too strong can actually backfire. Areas that are treated with this overly concentrated spray will be repellent and insects will simply avoid the treated areas prolonging the infestation.
Permethrin SFR is not labeled for use on clothing and is not formulated for such a use. We do carry a permethrin-based product called JT Eaton KILLS Bedbugs, Ticks, and Mosquitoes that is labeled for use on clothing. It comes in a ready-to-use spray bottles and does not need to be diluted.
We do not recommend using Permethrin SFR in a fogger. The actual product label does have recommendations for using it in a fogger indoors, but only in very limited situations. We do carry concentrates that can be applied using a ULV fogger and thermal fogger.