To summarise - assuming that the JR freeware is referenced only in your routes config.txt file and you are not actually putting the freeware assets into their own .cdp files and bundling them with your route.
If the JR freeware you are using is from the DLS and the .cdp package you are uploading is going to the DLS then there is no need to seek permission or approval - the content creator (e.g. JR) gave that approval when they uploaded their content to the DLS.
If the JR freeware is only available on JRs web site and you upload the package to the DLS then, again, there is no need to seek permission BUT you should inform potential downloaders, ideally in the routes description tag, that some content is freeware found at JR and give the web address for those people, like me, who have never been there. It is important to mention that the content is "freeware" otherwise it may deter any potential downloaders who may think "JR = payware".
Anything else that involves placing the actual freeware assets into their own .cdp files for redistribution, even though they may be freeware, would require permission from JR. The only reason I could think of for why you would need to do this would be if the assets were not available anywhere (not on the DLS or JR).