Sunwise, there are probably more sunny days in Plovdiv than in Byala. But no coastline. Just Maritza.
Regarding snowboarding - that is not possible in Plovdiv. The nearest locations are probably Chepelare and Pamporovo. Though some smaller places could be closer.
Cars - if more than one there are basically two options - hiring s.o. to drive the cars to Bulgaria or load the cars to a truck. Same applies for your dogs, and then you can register the beasts here. The cars will be somewhat dependent on Brexit, but just in case this happens you can reregister here. All the rest is standard - Technical inspection sertificate, Third party liability insurance and a road vignette.
English speaking solicitors are not hard to find, you will rather need an english speaking real estate agent before that. It will be a good approach to first select the location and then find a local real estate agent + solicitor.