Having read your post and understood that you don't wish to buy a new suit I'd say that if the dress code is black and white, then stick with that. Perhaps add some colour with your socks, pocket square, watch strap etc. If the dress code is semi-formal and no colours are specified, then you can choose a different colour tie as you see fit.
Check out Tumblr for menswear inspiration, see what you like and then head to Uniqlo, Topman, Asos, Zara, H&M etc for affordable versions of what you see. Classic knitwear items should last and tend not to go out of fashion - thick knit jumpers etc. Invest in a classic pair of boots that will stay with you for years, same with overcoat.
Generally I'd avoid this, and as other posters have pointed out the ones you pictured will not look great with a suit. If you're set on this look, then go for the simplest shoe you can and preferrably in white.
And as pointed out above, you may well get a different reaction in the streetwear forum.
In Vegas you're probably looking to keep it casual. Jeans and blazer is always a strong look, as long as everything fits well. So for instance, do not wear baggy jeans. Dark blue jeans and those chukkas with a white/blue/pink shirt will work very well. Below are some further options to inspire you