Am I correct to note that Saturday the initial main squad needs to be announced?
Correct. Team rosters must include a minimum of 7 players by Saturday June 1 at noon Eastern US time.
From the TBT website:
III. TEAM ROSTERS
1. To be eligible to compete in the Tournament, a Team’s roster shall consist of at least seven (7) Players by 12 pm (NOON) ET on June 1, 2019.
a. A Team may add, but not subtract, Players after June 1, 2019 and up to seventy-two hours before the day of the Team’s first game, but only after Producer has received a $1,000 Player Registration Fee, as described immediately below in III, 2 or if the Team has accrued 1,000 registered supporters at least seventy-two (72) hours before the Team’s first game.
2. Any Team seeking to add a Player beyond the first nine (9) Players or add any Player after June 1, 2019 shall only be permitted to add the Player to the Team’s roster after a $1,000 Player Registration Fee has been received by the Producer or if that Team has accrued 1,000 registered supporters before seventy-two hours before its first game.
a. The $1,000 Player Registration Fee must be paid to Producer prior to the registration of Players ten (10) through eighteen (18). A Team may add a Player after the Tournament has begun only after advancing to Round 4. The Player Registration Fee for adding a Player before Round 4 shall be $2,000.
b. A Team that has accrued 1,000 registered supporters prior to 72 hours before its first game shall be permitted to add a tenth Player without paying the $1,000 Player Registration Fee.
c. A Team that has accrued 3,000 registered supporters prior to 72 hours before its first game shall be permitted to add an eleventh Player without paying an additional $1,000 Player Registration Fee.
i. Example A: Team A has nine (9) Players and wants to add two (2) Players before it plays a game in the Tournament. The Player Registration Fee is $1,000 per Player. Thus, Player Registration Fees totaling $2,000 ($1,000 per Player) must be received by Producer prior to the additional Players being permitted to play for Team A.
ii. Example B: Team B has 9 Players and wants to add a Player for its first round game. The Player Registration Fee is $1,000. Team B then wins its first three games and wants to add an 11th Player for its fourth round game. The Player Registration Fee is $2,000.