A seven letter word for lasts is endures.
A seven-letter word meaning serious and eager could be "earnest".
earnest
Debacle
The seven letters, mcuanst, can be formed into the seven letter word, sanctum. Sanctum is an English word meaning 'a sacred place.'
The second letter of the seven letter word meaning "one-fourth" is "u." The word is "quarter."u as in quarter
A seven-letter word meaning 'including everything' is 'overall'.
A seven letter word for lasts is endures.
uncover
surreal
missing
desired
slander
getaway
consent
optical?
poached