If the Personal Progress site functions the same as other sites and tools for out of unit leaders, then the out of unit leader needs to not only have an out of unit record
recorded in MLS but also be listed with a standard position
.The out of unit record for the branch president must include priesthood ordinance information. The out of unit Laurel leader must hold one of the following positions; Young Women president, counselors, and secretary; Laurel, Mia Maid, and Beehive adviser. For a Laurel leader the position would have to be Laurel Adviser.
The Personal Progress site Frequently Ask Questions
page, question 11, only mentions bishop, bishopric first counselor, and bishopric second counselor and does not address branch president and presidency. I strongly suspect the branch president and presidency is included when speaking about the bishop and bishopric.
If the branch president has access to LDS.org Leader Resources for the branch then he should have access as a leader to the Personal Progress site.
If the branch president or the Laurel leader hold positions in their home unit then it is possible those positions are overriding their out of unit callings for the purpose of accessing the Personal Progress site. While it is not likely they would have dual callings, I thought I'd mention it.