Mendicants are not permitted alternatvies.
Answer:Beggars can't be choosers.

Male cadavers are incapable of rendering any testimony.
Answer:Dead men tell no tales.

Neophyte's serendipity.
Answer:Beginner's luck.

A revolving lithic conglomerate accumulates no congeries of small, green, biophytic plants.
Answer:A rolling stone gathers no moss.

Members of an avian species of identical plumage tend to congregate.
Answer:Birds of a feather flock together.

Pulchritude possesses solely cutaneous profundity.
Answer:Beauty is only skin-deep.

Freedom from incrustations of grime is contiguous to rectitude.
Answer:Cleanliness is next to godliness.

It is fruitless to become lachrymose of precipitately departed lacteal fluid.
Answer:There's no use crying over spilt milk.

Eschew the implement of correction and vitiate the scion.
Answer:Spare the rod and spoil the child.

The stylus is more potent than the rapier.
Answer:The pen is mightier than the sword.

It is fruitless to attempt to indoctrinate a superannuated canine with innovative maneuvers.
Answer:You can't teach an old dog new tricks.

Surveillance should precede saltation.
Answer:Look before you leap.

Scintillate, scintillate, asteroid minim. (not a proverb)
Answer:Twinkle, twinkle, little star.

The person presenting the ultimate cachinnation possesses thereby the optimal cachinnation.
Answer:He who laughs last, laughs best.

Exclusive dedication to necessitous chores without interludes of hedonistic diversion renders John a hebetudinous fellow.
Answer:All work and no play makes Jack a dull boy.

Individuals who make their abodes in vitreous edifices would be advised to refrain from catapulting petrious projectiles.
Answer:Those who live in glass houses shouldn't throw stones.

Where there are visible vapors having their provenance in ignited carbonaceous materials, there is conflagration.
Answer:Where there's smoke, there's fire.