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While they are drying I notice water droplets on the paper leave behind spots and only if i wipe off the print completely right after washing and do not hang to dry this is avoided.
You can safely squeegee your prints when they come out of the wash and then hang to dry. If this helps with the drying marks, there's nothing wrong with doing so, provided you use a clean and supple squeegee that doesn't mar or scratch your prints. RC paper is pretty forgiving.
I have tried to wash the prints again in case all the fixer wasn’t removed the first time and I notice that when the water hits the paper the color changes but goes back to normal once dry (this shouldn’t be happening if the fixer worked, right?).
It's common that an image in a gelatin emulsion will look differently when wet. The effect is often called 'dry down' especially in the context of fiber-based B&W paper, but it's a common phenomenon with many gelatin photo materials. Because of the nature of the image in a lumen print (very teeny tiny silver particles), it's quite plausible that these prints also show very pronounced dry-down behavior. So no, this is not indicative of a problem with your fixer.
All of this leads me to believe that they aren't fixing correctly
I see no evidence of this. But if you're concerned about whether the fixer is doing its work, try and taking a scrap print that you've processed normally, and then dipping half of it into a tray of paper developer. If it turns dark or even black, you know that there is developable silver left in the paper and the fixer apparently didn't get all of it out. The test is slightly tricky with lumen prints because I'm not quite sure if the tiny silver particles that make up the image will quite withstand the developer, but I'd expect the image to remain unchanged - at least after another wash and after drying.
I really want to perfect my method and be able to display my prints.
Keep in mind that the image on lumen prints is really, really delicate. As the problem with the water droplets showed, these tiny silver particles easily bleach out even under the influence of factors that will leave a normal B&W print totally unaffected. This has implications for their archival stability, and may be of concern in a display/exhibition setting as well. If these works are intended to last, I'd look into display conditions and ensure the prints are properly framed, preferably behind UV-blocking glass, and that display lighting is free of UV as well (modern LED lighting is usually a good choice).
It's possible that additional chemical protection such as a treatment with Adostab might help as well.