#2. I dont think its time wasting so long as done with respect. Unless I am booking a regular, I would typically blast simple enqueries (i.e. rates and time availability) to a small numbers of providers that I am intersted at. If time and rates meet my budget and schedule, then proceed to raise a more detailed questions. Otherwise, politely inform them their rate/ schedule doesnt work for me; and move on. Never haggle. Time needed to filter providers solely based on rate and timing suitability is rather short; it aint a whole day process.
Its common business practice for company to request fee quote from multiple firms at the same time; compares such fee quotes and then decides on the firm who is most suited for their needs at that time. Its the cost of doing business. How is it any difference with providers?