Colin, the short answer is it's possible. The other short answer is I'm not sure how far down the rabbit hole I want to go with token settings. There are 53 writeable token properties currently exposed to the api. I'll have to think about this for a bit. I'm also knee-deep in a tricky bit of coding with another one of my scripts that I'm trying to update in the next few days so that is taking a lot of my free time.
Re: DM Eddie's suggestion, I was hoping that would work but when I tried it out I got no love. The idea is to use the --ability|<abilityName> command to fire an ability from a character sheet (defined by --sheet|<sheetName> if it exists somewhere besides the selected token's sheet) that would contain the token-mod syntax.
For example, I tried using a character named "MacroMule" and added the following ability named "SetAura10Target":
!token-mod --ignore_selected --ids @{target|choose target for aura|token_id} --set aura1_radius|10ft
Then tried a test Spawn call using the following:
!Spawn {{
--name|imp
--offset|1,0
--sheet|MacroMule
--ability|SetAura10Target
}}
However, token-mod seemed to ignore the --ignore_selected in the ability and added the aura to my selected token anyway! Probably the presence of the @{target} reference in the subordinate ability screwing things up(?). The token-mod ability works when called directly, but not from the Spawn script. Sad face.
Going back to the original topic: Maybe an easier solution that having me basically replicate all of token-mod within the Spawn script (barf) might be to add something akin to the Scriptcards way to fire an api call. I have all of the spawned token ids at the time of creation. I could store those and then add a --tokenMod command that would read in your token-mod syntax and automatically add the spawned ids and ignore_selected so it would do the stuff to only the spawned token(s). Or maybe make it more generic to add any api call, something like --api|<stuff> . Dunno, just a thought. Like I said, I'll have to think about it a bit when I'm not buried in other projects.