Interesting - and a much after period than is typically gamed, which is why I suspect TMWBK is used as the base game
Typically Pikeman’s Lament is being used for Sengoku era battles - which makes sense as they are from the same period.
Pikemans Lament is indeed to date the goto for those gaming Samurai with the Rampant stable of rules. Especially since there are army lists provided and a follow up expanding article was published in an issue of Wargames Soldiers Strategy.
What I would point out that is maybe being missed about why TMWWBKs being used is that was written solely by Mr Mersey, Pikemans was co-authored with Michael Leck who is not employed or associated with Edinburgh Universaty at present.
My view is that it fits better in the fortcoming edition then roll with it, or adapt the ideas to Pikemans. There close enough core system that switching up or using the ideas shouldn't really cause an either or situation.