I was under the impression that the units that show up during a request first were only those units that did not get matched by an ongoing request. ....
Request first IS a form of ongoing request. There are debates here as to whether II gives higher priority to ongoing requests that are request first versus ongoing requests that are deposit first, but no one really knows. If anything, the thought (or fear) is that request first will be given higher priority than deposit first, because with deposit first, II has already got your week. However, I use deposit first anyway, because I like getting bonus weeks (ACs).
What you may be thinking is that ongoing requests are given higher priority than
online searches. That is definitely true.
Disney does deposit Boardwalk and Beach Club 1-bdrms and 2-bdrms, but they are much rarer than OKW or SSR.