Considering Cam hasn't yet competed a full year as a full time pro, having started with last year's grass season, these are great testaments to his progress.
This time next year Cam will be above Kyle in the rankings and Gabi above Heather. Flag this up then
Kyle vs Cam is interesting, because Kyle is still progressing upwards too, and Cam is not exactly shooting up just yet. Gabi vs Heather on present trends is not a difficult call. In fact I think it will be sooner than one year - essentially come Fed Cup time next Feb and it won't be Heather playing singles for GB. I would expect it to be Gabi, but there may be other challengers including Katie B. In fact even if Jo was not to play in Feb, I still don't think Heather will play in the singles. She'd certainly have to chuck Jeremy Bates very soon, if she does want a chance of being there!
This time next year I'm pretty confident that Kyle will still be above Cam in the rankings and Heather still above Gabi and I thus boldly predict as such.
Heather I think will still essentially be a better player than Gabi this time next year and even more likely to be higher ranked than Gabi based on counters for the full year up until then. Jeremy Bates can't fundamentally change that balance enough err I don't think and things may have moved on anyway. Gabi has done really well but has still got to prove she can regularly beat the higher ranked players that she is likely to need to do to continue big enough increases up the rankings to move ahead of Heather.
I hope Cam does continue to really progress well but I simply don't see him catching Kyle in the rankings.