Scaredy cat

We have two cats, and one is a scaredy cat.  I watched Quantum and Tangle yesterday as we heard Hubby came up the steps to the front door.  Quantum sauntered over to the door hoping for interesting sights and a belly rub.  Tangle froze as soon as he heard footsteps then bolted for the kitchen as the door opened.  He hides in the basement or the closet when we have company over, even really quiet and gentle company.  He's a beautiful ginger cat with beige swirls on his coat, he makes these cute chirping noises, and I'd love him to come out and be adored by other people.  Quantum is the dominant cat, but Tangle still chases, pounces on, and wrestles with her.  He's not afraid of her, and he got used to Larry and Sarah after a while.  Anyone got hints on making him less afraid of people?  How do you reassure a cat that strangers are OK?

Quantum doesn't care who's around or what they do, so long as there are shoes to investigate.  When we first got her, the homegroup we had at the time all wanted to play with her and pass her around, so she's used to people.  Tangle's super affectionate, very cuddly, but only with us.  We didn't have a group meeting in the house when we got him, and I had got a job, so he's used to an empty house.  He ended up in the basement this weekend because of the VLI intensive and the stranger in the house.  When I went to find him he was so grateful for the company he curled up and purred in my lap for ages.  He's a fidget, so he changed position every minute or so, always trying to get closer.  We're leaving for a week and I want him to get on with the house sitter, rather than hiding in the basement.