SHF has always claimed to have had assistance for the Sacrament of Confirmation and holy oils from retired or current bishops from the Novus Ordo, so I would think they do consider the New Rites in general to be valid (if validly celebrated).

That is a stretch.

To my knowledge Servants of the Holy Family has considered the Novus Ordo to be “questionably valid” and does not recommend for laity to participate in it, even when no other Mass is available. 

This is a separate topic from whether someone is a legitimate bishop or not.