I am wondering if it is possible for my tiny group of aspiring landsknechte to be involved in other late medieval gatherings ( set 1500 latest), and still retain some technical correctness.
I very much doubt if the landsknechte inspired "slash and puff" had a definite cut-in date, but would like to hear more learned views about the probable styles of early clothing and armour bits, from about 1470.
Is it the "slash & puff" that you are looking for? https://commons.wikimedia.org/wiki/File:Two_soldiers_in_battle_at_O...(8579777716).jpg
Paul Dolstein's sketches of early Landsknechte in Sweden does not show any slashing yet in 1502. They definitely used the term Landsknecht then and the king of Sweden was so impressed with how they defeated the peasant uprising that he supposedly knighted them all (if they promised to leave Sweden) which helped create the alternate name "Land Knights."
By the battle of Ravenna (1512) artwork depicts at least puff&slash sleeves. https://en.wikipedia.org/wiki/Battle_of_Ravenna_(1512)
I heard an old reenactor tell a story (c. 1979) about a HRE prince who liked to play mercenary with the Italian city states. He received work of an uprising at home so had his soldiers drop armour for a faster march home. Knowing that it was colder back home they scavenged extra clothes parts off a recent battle field. Fortunately sleeves were laced on at that time and allowed for layering. They made it back just in time to fight where their layered clothes were slashed up without armour. A messenger saw this bright slashing from a distance and mistook it for the latest Italian fashion so road home to tell everyone who then slashed up their best clothes in imitation. Not wanting to admit their embarrassment they just played it off. Good story and plausible but I have never been able to find clear documentation of such a battle in the correct 1502-1512 period.