If they will/can have multiple days in DCA (or if they have hoppers), another option to meet Olaf is to try Olaf's Snow Fest at night. Two nights this week, we went into the Olaf's Snow Fest area an hour or two before DCA's 10 PM closing with absolutely no wait at all. When we first went in on Sunday night about 9 PM, Olaf's greet line was closed but the "snow" area opened up so we waited in a slow line to go "sledding." By the time we got done sledding, Olaf was available again, with a line of about 2 families.
Monday night, we just went in to Olaf's Snow Fest about 8 PM because my friend wanted a photo with a "snowball" made of the snow/shaved ice, but there was again no line to get in. I'm almost certain we could have met Olaf then if needed, though we didn't try.
I'm not sure I would risk pushing meeting Olaf back so far in the day if they didn't have multiple days they could try, just in case Disney changes something or crowds cause there to be long lines at night, but it worked out perfectly when we tried it.
Our experience this week was that the return times on the Anna and Elsa FPs were significantly earlier than the return times on the FPs for RSR, so I assume Anna and Elsa's FPs last longer. I wouldn't worry about getting them super early...in ANY circumstance, I reckon the first couple hours should be fine. Pulling FPs for Anna and Elsa a little after 10:30 on Monday gave us a return time in the ballpark of 1:10.
I don't think anything's changed as far as TSMM, so it's just a matter of picking and choosing if they want to rush to do it or wait a bit and risk longer lines. IF they have multiple days in which they could meet Olaf if needed and can stay in the parks late, my plan would probably be:
*RSR (ride it if it's not an "Extra Magic Hour" day for hotel guests and they can get there early; otherwise skip)
*RSR FP
*TSMM
*Anna and Elsa FP (send a runner if possible)
*Paradise Pier rides? or Bugs Land if that's their thing
*Sing Along FP when their window opens
*Olaf's Snow Fest about 8 PM
If they can't possibly meet Olaf late or only have one possible day to meet him, I'd probably head to Olaf's Snow Fest first and then get the RSR FP afterward (or if there's a line for pagers, send a runner to get the RSR FP if possible, assuming the whole party doesn't have to be present to get the pager). That will mean a longer line for TSMM whatever they do, but that can't be helped.
We did not do the sing-along. We did go to the Frozen show in
Disneyland (first showing of the day with a FP). It was a good show, but the queue and seating situation was nearly a mob with poor routing of crowds and the high that day was about 91, so it was really pretty grim getting in there and watching it. Several people had some strong words for CMs (not yelling but sternly telling them to fix the problems caused by poor routing and overcrowding). My seat was very bad and in partial sun, and my friend left to watch from outside the theater in the shade. If they want to do that show, I'd suggest they maybe try to get the latest showtime (if the weather is hot) and that they get in line at the beginning of their FP window or earlier if it's possible.
(If they are not used to FPs, they might need to be extra careful not to get the Frozen FPs mixed up. They all look alike if you don't look too close...)
I know it wasn't on their list, but Mater's Junkyard Jamboree is definitely worth doing. I find the queue pleasant enough if it's a 10- or even 15-minute wait because of the music...but all 3 days, it was a walk-on for the last hour or so that DCA was open (whether it was a 9 PM close or 10 PM).
