Distinguishing between my personal acknowledgements and those of all authors
Is it acceptable to thank the co-authors for guidance, encouragement, etc.?


No, not really. Well, it may be going a bit far to say that doing so would be unacceptable, but I can say two things:


I have never seen an author thanking one of their coauthors.
Thanking your coauthors in your own joint paper with them is illogical. The purpose of the acknowledgements section is to provide a space where the contributions of people other than the paper's authors, which were of too minor a nature to merit authorship, can be acknowledged, so that those people would get some minor (mostly of a psychological, feel-good nature) credit for their help. Your coauthors are already getting a much more major credit than that, so an acknowledgement to them adds nothing. 


To summarize, if you want to thank your coauthors, do it in person. I'm sure they would appreciate it.