First off, they don't need to be intense lessons. You just want to be able to ...
* Play a four-part piece on the piano.
* Be able to sing pitches in tune.
Seriously, I regret that I was forced to take piano lessons at a young age and then I abandoned it. I can play a four-part piece (soprano, alto, tenor, bass) from a vocal lead sheet, but VERY slowly. Hey, if you're in just about ANY professional capacity, it's EXTREMELY helpful to be able to play piano.
The singing is another thing. While it would be great if you could see a middle C on the score and sing the correct pitch (and in tune) for your out-of-tune oboe player (pick, pick), the best that most people could do is sing a part in relative pitch -- that is, you can sing the intervals properly if you have a starting pitch.
Again, you don't need intense lessons.
For me, while I had been in a lot of choirs through high school, I never developed a good singing voice until I was in my late 20's and people wanted me to sing in their various groups. From my late 20's to mid 30's, I took lessons from a couple pro singers/educators and I found that I actually had some singing talent. That's also a kewl thing.