When selecting music for yourself or your students, you should always take the utmost care to select pieces that are appropriately leveled. By doing this, you will progress more quickly through the music and be able to focus your time and attention on making music, not squawking out the notes at the proper time.
I have encountered many people, recently, who are just interested in playing the proper notes of the pieces at close to the right time. Their interpretations of pitch are not always the same as mine. I would prefer the proper note also be an in tune note. I would prefer that proper timing mean that each person is internalizing the beat in the same way.
I consider playing the proper pitch (with no consideration for tuning) at close to the right time to be the “horn” method of playing strings. Honking out notes with no regard for tuning, tone, or exceptional rhythm is a crime against the instrument itself. There is no need for this kind of playing. If you are doing it right, the music should flow easily from your instrument, allowing you to achieve a higher sense of musicality in every performance.
As for adequate rehearsal of pieces, there is no better goal for a piece than to have it polished to a performance quality. Practicing parts outside of rehearsal is necessary. When playing with an ensemble, you should always take great care to pay attention to details that will make the performance more exciting.
Well rehearsed, appropriately leveled music will lead to success by you and your students and ensembles in the long run. Use caution. Anyone can play the violin, but it takes great care to do it well.