With lymph nodes involved they may, rather than instant surgery go for the chemo treatment first which will give you symptoms similar to the flu. Close family and friends who will be visiting you will need to be aware of infection risks. Its not you to them, its them to you as your immunity will be lowered.
For the young kids, tell them about it but also instill that this is a bit of a trial and an illness you are fully going to beat! It wouldn't hurt to make their school teachers aware as well so perhaps your son has someone to confide in there if needed.
It is very frightening at first but knowledge is power so read all the bnca links and get a bit of a handle on it. We are all here for you with no judgement, only support. Hugz <3