Paradis/Ouellette in 2014 picked up a spot at Skate America based on just their fifth-place score at Nebelhorn -- before that season (where they were also given a host spot at Skate Canada), they hadn't competed at any international more prestigious than Cup of Nice, had never medaled nationally at junior or senior, and the dance field is typically larger than pairs so there shouldn't have been considerable desperation on USFSA's part.
The top-5 athlete replacement list rules were ignored quite a big in the past, but the list was expanded to 10 last season, and I don't recall the expanded list being ignored. Historically, athletes have been invited to GPs due to Challenger scores & placements without a win, but the exception isn't written into the rules and was not made last season. We shall just have to watch and see if there are any selections from outside the replacement list this year.
I don't recall the timing for Paradis & Ouellette's replacement, but I do remember Stephen Carriere being a last minute replacement at SC. Skaters just across the border--or training in the same country--are sometimes the only athletes who can get there on time, and it is nice to see those last minute replacements filled. Every year athletes drop out due to illness, and we often end up with smaller fields.