Craft a musical arrangement that integrates the provided motif and upholds the required musical structure.
X:1
L:1/8
Q:1/4=140
M:4/4
K:Bb
['BdFB DFBd fbdf BdcB', 'f2 f2'  
X:1
L:1/8
Q:1/4=140
M:4/4
K:Bb
 dc |S BdFB DFBd | fbdf BdcB | AB=Bc ^cde=e | f=egf _ecAF | BdFB DFBd | fbdf BdcB | Agfe dcBA | 
 B2 B2 B2 :: cB | Afcf Afcf | AFAc fcAF | dfBf dfBf | dBdf bfdB | =egcg egcg | =eceg bgec | 
 fcaf =ecbg |1 f2 f2 f2 :|2 f=efg f_edc |]"_Alternative ending" fafa gbeg | fefg f2 |]  