TBH I don't think Dora is completely impossible for DLC
The main thing holding Dora back is her brand image - and even then Nick have been experimenting with the whole "growing with the audience" thing. Lost City of Gold was rated PG and they're making a new series aimed at a slightly older audience - hell, Nick have shown willingness to do
dark things with long-gone Nick Jr. characters in the past.
I think above all it comes down to whether 1. Ludosity want Dora, and 2. Ludosity can, should Nick have requirements, settle for a live action Dora.
However, I don't think Dora is likely either - those last two factors are very big, especially the latter.
Now, Hugh on the other hand? I'd say he's very likely. If we get Jimmy, Donut Boy's probably not far behind. Rep partook in the Hugh AMA, there's no Neutron rights issues, the support is clearly at least semi-earnest, he has more moveset potential than a majority of the Neutron cast... the only reason I can see him not getting in is because he's seen as a low priority or they want to expand the list of shows as opposed to adding more characters from shows already in.