Criteria used by pinch hitter choice

In BTT90s

I know Mike Lansing's year is either 1994 or 1995. Lansing (a RHB) was pinch hit for Dawson (RHB) against Melido Perez, whos is a RHP. Was Dawson chosen as the pinch hitter because his chances against RHP are simply more favorable than Lansing's chances or is there another reason?

It is really, really dangerous to try to read too much into the decisions HAL makes, especially with only this one example. Too often, there is no rhyme or reason to what HAL does, at least that most of us can figure out. Having said that, here goes:
You know that Lansing is both on one of his weakest 2 cards and on 2 cards that lean lefty, one of them to 3L (95), which is a significant lean. Melido Perez is right-handed. Andre Dawson has a couple of cards which are either even (92)or lean towards righty pitchers (90), and one card which is 3L but has better numbers than Lansing's 3L card. And you were down a run in the 8th inning, and needed a big hit.
In the absence of any other information, I would take this as a POSSIBLE signal that Dawson is either on his 90 or 92 card, with 91 being a more remote possibility. I would want more numbers for Dawson, and/or more examples of Dawson being inserted as a pinch-hitter, before I felt at all secure about that possible conclusion. All in all, I would keep an eye out and hope that this is a sign that you have a good card reveal for Dawson.