blimey, the future is here. Every thread comes with new, improved references to AI ... hurrah. Let's hope it can find jobs for all the people it's going to put out of work.
anyhow, yes - normally your photos here and on the blog are great, which is why I commented.
assuming your photos are going onto a PC before uploading, the basic Windows photo program should have an 'auto' adjust feature as Vexillia says - generally making a worthwhile improvement. May well do the job.
Should be the same kind of feature if you're using a phone for the pics.
I'm not sure if an older style camera like the Ixus would have such a thing, although you should be able to adust it's white balance in the settings at the least.
It made a great job of those 'en masse' pictures you've posted, given the mixed lighting situation you describe tho'.
Vexillia's photo above - no need to remove the b/ground (using AI or not) imo - looks more natural (less obviously processed) with some impression of actual enviromnent, as you normally do.
not sure what software he used, but the figures still seem to have a somewhat 'veiling' cast to me - not your usual clarity - I guess the cast at time of taking was very bad - so auto stuff doesn't make it perfect.
* actually, thinking about it: if Vexillia removed the b/ground before doing the auto-adjust that might explain why the auto white balance correction hasn't worked that well.
Making the/bground bright 'full' white' would skew the result. Another reason not to do that possibly.