You're wrong, mate. Barca still own them, they have the players on their books. There hasn't been a single rumour about them not being able to register their loaned out players in the Spanish media, so I don't think they are losing sleep over this.
Having a player on your book is different from having a player registered.
A player must be registered at an association to play for a club
as either a professional or an amateur in accordance with the
provisions of article 2. Only registered players are eligible to
participate in organised football. By the act of registering, a
player agrees to abide by the statutes and regulations of FIFA, the
confederations and the associations.
2. A player may only be registered with one club at a time.
3. Players may be registered with a maximum of three clubs during
one season. During this period, the player is only eligible to play
offi cial matches for two clubs. As an exception to this rule, a player
moving between two clubs belonging to associations with overlapping
seasons (i.e. start of the season in summer/autumn as opposed to
winter/spring) may be eligible to play in offi cial matches for a third
club during the relevant season, provided he has fully complied with
his contractual obligations towards his previous clubs. Equally, the
provisions relating to the registration periods (article 6) as well as to the
minimum length of a contract (article 18 paragraph 2) must be respected.
4. Under all circumstances, due consideration must be given to the
sporting integrity of the competition. In particular, a player may not
play offi cial matches for more than two clubs competing in the same
national championship or cup during the same season, subject to
stricter individual competition regulations of member associations.