I would like to do some checks with slave nodes from master when they get online and startup-trigger seems the right plugin to use for that.

Unfortunately it is not possible to use the triggering node name as a parameter other than Node/Label, like e.g. simply passing it on to another job as a string parameter.

My specific use case is to update the slave.jar on windows slaves from a job that runs on (Linux) master (and utilizes ssh to do so). Currently this is done manually whenever the versions are found to not match but would be nice to have this done automatically when the slave nodes start.