Looking to buy these watches - what do you think? How much are they worth?

I kind of admire your enthusiasm but you really need to cool it. Of the three above, the Cosmic is quite nice, the 471 I have no idea and the subsecond auto is an overpolished redial. If these are being offered you by your colleague, he is either trying to unload some duds or does not really know what is good and what isn't. I was going to add that you're asking us to do all the work for you, but I see someone else has just pointed that out.
Your options are either to buy something now on the spur of the moment and probably regret it or take your time to do your own research, which is what the rest of us have had to do.
To sum up, I think you've had your quota of free advice. I like the black Seamaster and the Cosmic. For prices, search ebay completed listings and the For Sale section here.

Thanks guys.
I am asking because I have done some research and can't find anything about these watches. My research led me to this forum.
I also find Ebay very vague and misleading for sold items. What I am hearing is that this is not an exact science, so I will take these items to a qualified vintage watch appraiser and get a better sense of value.

I really appreciate your feedback, not looking for a free ride, just some expertise in something that I an new to.
Cheers.

Thank you. I did look at it - very interesting.

Here's a very old sales post with a great watch (that will almost certainly appreciate) as well as an example of a case that has never been polished.

https://omegaforums.net/threads/195...l-354-white-gold-arrowheads.9080/#post-106586

Now the members here have spent years looking for examples like this and most of us have paid some school fees buying poor examples before we learnt what not to buy. There are collectors here who maybe buy only one or two watches a year, solely because they want only great pieces and poor or mediocre ones similar to those you have shown hold no interest. Also, for many here the hunt is as much fun as the ownership.
I think you need to make a decision, do you want the first ones you find (and pay the school fees) or are you prepared to take your time, learn and find the collector grade watches?
Some threads I would recommend are WRUW (where the good stuff is put on display) the sales threads, if you sell here you have to be honest or you will be shot down. There's also a thread along the lines of what omega did you buy for less than $500 which will show you the bargains the people with knowledge have bought.
Good luck