Ricky Whittle should be fine - Natalie L's pro storyline suggests that she'll be praised for her choreography this week after being criticised last week (as with Brian earlier in the series) and it's in her wheelhouse anyway. Given what we've seen of her routines so far she excels at Hollywood glamour style.
I can see Ali going 39 for her foxtrot easy, so she should be fine as well, unless the lower order conspire against her in terms of the order of voting.
Chris seems popular enough to dodge the bottom 2 (although so did Tuffers alledgedly) no matter how badly he dances, which probably leaves by now perennial bottom 2 placer Ricky Groves against one of Natalie, Jade or Laila. If it's the former he'll almost certainly go, but if it's one of the latter 2 (and I think people are over-estimating the likelihood of a second week of public sympathy significantly in both cases) they might drag him out 1 week longer, rather than take a seriously injured dancer into the 2 dance stage, which almost certainly starts next week, and also to even the genders up again.
Of course a lot of that depends on whether Jade dances at all, and if she does whether she rumbas (almost certainly bad) or tangos (probably alright, but probably muted by injury, leading the public to wonder what all the fuss was about).