No permission is required from Spouse, Doctor, or Attorney, to obtain your alleged children samples. Special samples can be used with the home DNA test kit, however, additional charges apply. See this link for special sample pricing. The additional cost is not refunded if no DNA is present on the special sample. If the alleged fathers are brothers or father and son then they should each be tested at the same time.
Related individuals share more of their genetic code than unrelated individuals.
When there are related possible fathers, not testing all parties could result in falsely implicating the alleged father. If the subjects are in different cities then we recommend that the kit be sent to the other person first. You take your sample and mail it to the lab in the included mailer. See this link for more information. For purposes of identify testing, there is no difference in DNA derived from buccal swabs or blood.