Good job! I'm with Alex & the others on the phone calls. You're under no obligation to take the call. Dh & I are very untied from the phone & often let it go to voicemail, as calls tend to come at inopportune times in the evening. There's no rule that having a phone obligates you to answer it.
I also let personal calls go to VM at work, depending. Sometimes I'm just working on something & I don't want to stop in the middle.
Hopefully they will email or leave a message identifying the dish, if they want you to provide something. If you don't hear anything, just make something easy you think will fit in with their tastes, send it with dh, & give it no more thought. You did a great job navigating this.