They can, however, if you (generally) do bad deeds and at the same time try to speak gently from time to time - this will lead you nowhere, because you are trying first to fix things which must be fixed later.Well, what I'm practicing is pretty simple. For verbal, I'm practicing greeting my coworkers in a friendly manner in the morning. For mental, I'm making sure to take a pause once a day and spend a minute reflecting on my good qualities. For bodily, I'm practicing a small act of generosity, like giving a $1 donation when getting a coffee or going out of my way to help someone. These are small acts and I don't see why they can't be done in parallel.
Same with meditation. For example, yes, you can meditate 10 minutes a day - but generally this will lead you nowhere until you are proficient in previous preliminary path stages. However, once you are accomplished in that, every meditation session will give you significant boost and advancement - like it was with the Buddha himself. He was so prepared, that he just sat under the tree and accidentally entered jhana. He didn't need to meditate 8 hours every day for 30 years to make it - because other things lead you in there, not "as many sessions as possible".
This gradual approach to practice is something people poorly understand, unfortunately.