I’ve only bought pre owned watches in this price range, and my experience has always been positive. Maybe I’ve just been lucky, but when the seller has 99.999999% positive ratings, I usually take that as a good indicator. I’d like to point out one interesting website I came across: davidsw.com. The prices seem really good, and people on watch forums seem to love this guy. So, if you find anything interesting here, I would like to know what is your experience.
As for pro/con of each brand - it’s mostly a matter of taste. These are jewelry pieces, after all. I would avoid models with documented quality issues (Tag Carrera 16, for instance, is said to have issues with the chronograph buttons coming out). Resale value might be a consideration (Rolex, Patek Phillipe are the best), and will affect the difference between full retail and grey market prices. Plus, you never know if you will end up selling your watch at some point.
Another thing people don’t consider much is maintenance cost. Typically, you are supposed to service these watches every 5-6 years. Budget about 10% of the price for each service. I have a feeling you are not a Rolex guy, but I should once again bring up this brand, since it is the cheapest to maintain among those in a similar price range. Servicing a Rolex might cost $450, but IWC will be $700. Watches with complications, like chronographs, will cost more to service.
I think the watches you chose are fine, except the Tag Heuer. If you want a Carrera, you should go for at least the Calibre 1887, which is an in house movement and a “big thing”. Otherwise, watch people will turn their nose up at you. Of IWC and B&M, IWC is the “better” brand, but if that particular Baume et Mercier appeals to you, don’t let brand reputation deter you. Other chronographs in your price range that I might suggest: Tudor Fastrider (Black Shield maybe, if you like the look), Bremont Alt something (which is a less austentatious British brand vs Breitling, or Omega Speedy obviously. If you are willing to look at grey market or used, your budget can get a Zenith El Primero, which is legendary as the “first” modern chronograph.
Regarding leather straps - my advice would be to get the metal strap first. Then buy an aftermarket leather strap if you want to swap the look at some point. It’s cheaper this way, compared to buying the metal strap later. Leather is more comfortable, and is lighter than metal straps. Weight is an odd thing to get used to in watches, but is apparent if you’ve never worn a heavy mechanical watch before. If your strap is very valuable (my watch has gold in the strap), you can curate it and instead, use a leather strap that you don’t mind scratching up (I do believe that these are made to be worn though). Otherwise, you can even get some Nato or other hipster crap that I don’t like, but people seem to be into.
Anyway, good luck and don’t get carried away.