Hey Howdy Hey Deborah and welcome to planDisney!
I bet you all are super excited about your Magical vacation just days away at this point! I'm glad you are doing your homework on purchasing your
Lightning Lane Multi Pass and Single Pass options. I will be happy to give you more details so you can better plan for the next phase in your vacation planning!
It sounds like you have already done the work on making sure everyone has a
My Disney Experience account and those that do not are managed by someone that does. No matter if this is an adult's account or a child's those that manage the accounts will be the only ones that can make purchases or plans on their behalf. So when it comes to purchasing Lightning Lanes, only the profiles that manage your husband, son-in-law and two kids accounts will have access to purchasing Lightning Lanes for them. This can be fine if you have separate people make the purchase and selection for these accounts. If you only want one account to manage these things, this will involve one extra step.
To give others in your Family & Friends list the ability to make plans with your managed profiles, you can easily do this from your My Disney Experience account. Once you log in, go to your "Family & Friends List". One the linked profiles you want to give access to, you should see a "settings" button next to their name. Click on that and then select the option to "Allow (person's name) to make plans for your managed profiles". This will then give them the option to purchase and make Lightning Lane selections for them so this can all be managed from one account rather than several.
Either way, you go, as long as you have these profiles created and managed accordingly, you should have no issues purchasing and making your Lightning Lane selections. Please let us know if you have any other questions, we are always happy to help!
To Infinity and Beyond,
Nick