Like I have said, PL/I did not have pointers in the beginning, i.e. since 1964 until July 1966.
So I think that this claim about Lawson having invented pointers comes from a misunderstanding. It is likely that Lawson has been the lead developer for adding pointers to PL/I.
Someone has heard this and because the first version of PL/I was developed during 1964, a false conclusion was inferred, i.e. that Lawson had invented pointers in 1964, before Euler.
That conclusion was wrong, because pointers have been added to PL/I much later, not during the initial development.
The paper written by Lawson about using pointers was sent for publication in August 1966, i.e. one month after the official introduction of a new PL/I version with pointers.
Due to the timing of the implementation of a PL/I extension with pointers, a short time after a public debate about how programming languages such as ALGOL must be improved, with most proposals integrated and analyzed in the papers published by Hoare, Wirth and a few others, I believe that it is rather certain that the impulse to add pointers to PL/I was not internal to IBM, but it was caused directly or indirectly by watching this debate.
The paper written by Radin, linked by you, confirms that IBM has added pointers to PL/I after an important customer, General Motors, has requested this, presumably in Q4 1965.
Because Lawson was the one who reported the end result of this work of extending PL/I with pointers, I assume that he was the lead developer of this project, which must have happened mostly during the first half of 1966.
As I have said, the only original element of the PL/I pointers was the "->" indirect addressing operator. Unlike in C, no other operator was needed, because PL/I followed the recommendation of Hoare, which was to use pointers only as structure members, where they are useful for implementing linked data structures, and not also as independent variables.
Therefore it seems likely that Harald Lawson was the one who invented the "->" operator.
However, he clearly had not invented pointers, as those (under the alternative name of "references") had been used earlier in the languages CPL and Euler and the implementation of pointers in PL/I done by Lawson followed closely the recommendations made by Hoare in his "Record Handling" paper.