FSSP (Fraternitas Sacerdotalis Sancti Petri) or Priestly Fraternity of St. Peter is a clerical society with pontifical rights.
They function just like any other religious order (Jesuits, MSC, SVD, etc). Members are limited to those who have received Holy Orders although they also confraternity for lay members.
They also have similar vow of obedience to local ordinary and superior as like other religious order. The only difference is members take oath to the fraternity.
In terms of education, FSSP runs 2 seminarians in Europe and USA so I doubt the claim that members do not have to have a degree.
As Latin rite clergies, they have the same right and obligation as other clergies. They can either pray the liturgy in Latin or the vernacular language wherever they are. Of course according to their spirituality, they say the liturgy in accordance to the 1962 liturgical books, which most of us know as Tridentine mass.
Hope this helps.