Recs of Handyman/Plumber

We’re considering installing a washer and dryer in our basement. Totally new to this and really looking forward to some answers from those who know better than us.

1. Who do we call? Plumber for the water pipes? Electrician for the wires? Whom should we call re the dryer vent? Is there one company than can do all 3? How much should this cost?

2. The apartment on the 1st floor already has a dryer vent that goes into the basement and then outside, so I’m thinking we can just join in. Are there any rules regarding 2 dryers venting into one pipe going outside?

Thanks!