ah - so we have gone over this in several threads now
your real goal here is to re-harmonise what is an essentially happy track
several approaches to do this
most obvious: substitute the relative minor for each major chord already identified for you (E->C#, A->F#m, B->G#m)
next obvious: substitute the chord a 3rd above the previously identified ones (E->G#m, A->C#m, B->D#m7b5, C#m->E)
every other possibility requires understanding of ii-V-I substitutions, where the final chord is deemed a temporary I|i chord (F#m-B7-E, Bm-E7-A, D#m7b5-G#7-C#m, C#m-F#7-B)
possibly use tritone substitutions
E-D#-C#m-B
Bb-A-G-F (won't sound pretty but is viable)