Note: I found the counterpart to Chemical Simulation, which the ustilagor had in 2E – it is now called Dissolving Touch. On a rewrite, I think we should add that.
Now, the vagabond has forced me to do a lot of research that I really should probably have done some time ago, but was too lazy.

regardless, I do know my psionic powers a bit better now, and how 2E powers relate to 3.5 ones.
In genereal, I think I will go with what the designer was thinking in 2E, and how that relates to 3.5 powers rather than what the 2E designer said and how that relates directly to 3.5 powers.
Here is where I'm going with that. " Vagabonds never have psychokinetic powers." Thus, they will not only have any 3.5 psychokinetics, but they also won't have any powers that were psychokinetic in 2E, including major creation, create sound, levitation, and matter manipulation.
"Clairsentience - Any power which lets them learn things." By "learn things", well basically any power in this category lets you learn something. I think they were suggesting it should have powers that let them gain specific information about a person, place, or thing.
" Psychometabolisrn - Any power which allows them to change form or travel in difficult terrain." The idea of changing form very slightly is present in a lot of psychometabolic powers, but I suspect they meant more like a total change in form rather than a change to form like gaining claws or fur. Naturally, anything that increases their ability to move in any way is good.
"Metapsionics - They are masters of this discipline, having access to all its powers without regard to their total number of disciplines, science, and devotions." Here is one that I'm going to have to enforce the "2E intent" idea. 2E Metapsionics and 3E Metacreativity seem to be defined in vastly different terms; in fact, it is likely that metapsionics was scrapped as a category, the powers eliminated, reassigned (most into telepathy), or made into feats, and Metacreativity was made whole cloth. Thus, they should have access to every power that translates well from a 2E metapsionic power, and I think they should have the option of getting metapsionic feats, possibly as bonus feats.
" Telepathy - The creature can use any telepathic power to communicate or gain information, plus enough attack forms to psionically defend themselves." That should be fairly clear. I'm going to give them access to the former attack/defense modes that are still Telepathy powers (not all are), and any power that is communication or information gaining in nature.
"Psychoportation - Any which allows them to travel." That should be the most obvious!

hello, anything goes from one place to another, including teleportation and planar effects, but also just anything that increases their movement capabilities.
With that in mind, I came up with a big list of good powers that seem to fit in well with the whole concept of the vagabond:
astral caravan, aura alteration, burst, call to mind, catapsi, clairvoyant sense, correspond, detect psionics, psionic dimension door, dimension slide, dimension swap, psionic divination, dream travel, ectoplasmic form, ego whip, empathy, empty mind, psionic ethereal jaunt, fate link, psionic fly, form of doom, fusion, id insinuation, psionic identify, metaconcert, metamorphosis, greater metamorphosis, psionic mind blank, mind probe, mind thrust, mindlink, missive, mass missive, oak body, object reading, psionic overland flight, psionic phase door, psionic plane shift, psionic blast, psychic chirurgery, psychic crush, read thoughts, remote viewing, schism, sensitivity to psychic impressions, shadow body, skate, psionic teleport, psionic teleportation circle, teleport trigger, thought shield, psionic tongues, tower of iron will, ultrablast, wall walker
I think the best way to handle its power list is the same way that the 2E designers did it: to not tie them down to a specific list. Thus, the template will state that they get X number of powers, and what their tendencies are (slightly modified from the 2E tendencies). The list of examples will be given in our example creature.
For the number of psionic powers a creature has, it should probably be some function based off of Charisma. Such as, Cha score x2, or 10 + (Cha mod x4) or something to that effect. As I previously determined, they will manifest powers as a 12th-level psion. When we decide what a vagabond's base Cha score should be, then it will be easier to come up with this formula. I estimated that it should have approximately 35 powers, though a vagabond fusing with a creature with a higher Cha-score would have more.