Katherine,
The ladies are doing a great job of talking through your options with you.

From what you've shared, it's sounding like you have your children pretty well-placed.

Based on the time and the level of content, you will definitely be able to give an American history credit for the work your 14 year old will do in Rev2Rev. Since the work is done in an integrated unit study type fashion, you have some choices as to how to award the credit. For example, you could award a full credit for American history up to 1900 this year and then award a full credit for American history from 1900 forward next year. Or, you could also ponder whether you wish to award any credit for government. If you desire to do so, you could add some of our suggestions for government and award .5 credit for government. If you did that, you could award .5 credit for American history this year and also award .5 credit for government. It is possible, depending on what you added for government, to also give a full credit for American history and .5 of a credit for government. Much of this will depend on whether you go the government route or not with Rev2Rev. There is much there in the program!
As far as your 9 and 11 year olds go, if they are avid readers and writers, then they should do fine in CTC. They will definitely need some training in doing the 'I' boxes on their own, but this will really help them so much in gaining independence as learners and in making sure they are getting many of the needed skills that are so often overlooked. CTC is a very rich program and is a year where the kiddos really make great gains in independence and maturity, both in their academic skills but also in their walk with the Lord. If you do end up with your children in CTC, I would encourage you to have your students in CTC do the Bible Quiet Time, rather than doing the Bible study in Beyond with your youngers. I think that having Bible time that targets the specific ages of the students can really address so many character issues, and this varies so much by age. So, while it is a great idea to have your family Bible time all together, I do you think you'll also reap much benefit by having the children in each guide also do their quiet time that is scheduled for their age. Through the quiet time studies in HOD, we have had the most wonderful personal discussions that would never have happened in a group setting.
When families do multiple guides, we usually recommend doing one storytime with all kiddos. So, you could easily do the Storytime from Beyond with everyone if desired. Or, you could use Beyond's storytime as bedtime reading (just making sure to do the follow-ups as they are so important).

You could definitely have the CTC pair do their own storytime readings, or have the 9 year old read the storytime books on his/her own and have the 11 year old only do the Extension books (but not the storytime books) on his/her own. They could just follow the schedule in the CTC guide to do their own readings for those areas.

Your child in Rev2Rev could also do just the Extensions on her own, omitting the Storytime books, or if she is an avid reader, she could read both the Storytime and the Extensions following the schedules in the guide. The questions for the Storytime in Rev2Rev are great for higher-level thinking, so you could just ask her those questions after the readings to dig a little deeper.
As far as the Bible Study goes, with your very large family in mind, I like 8arrow's possible suggestion of doing the 9, 11, and 14 year old together twice weekly for their Bible Time with you. To do this, you could potentially do either Who Is God? from Rev2Rev with your 9, 11, and 14 year old, or do Genesis: Finding Our Roots with all 3. Since both are scheduled twice weekly, it wouldn't affect the balance of the guides to do one with all 3. Then, the following year, you could possibly do the other one with all 3 that you didn't do the year before with them.
I also think that it would be possible for one of your olders to do LHTH with your youngers. My older sister has 7 children and had her oldest daughter do this with one of her littles. They had a wonderful time with it. It only takes 30 min. or less each day and requires no prep. or planning. So, this is an option too.
I agree that your 6 year olds and 7 year olds will fit well in Beyond. They should have such a fun year!

If you can try to get the left side of Beyond done in one 30 - 35 min. sitting each day that will help so much.

Then, the right side of Beyond is easily able to be fit in off and on throughout the day as time allows. This makes Beyond such an easy addition to the day.
The mix and balance of guides you have in HOD will definitely make doing 4 guides feasible. You have a great spread between the kiddos in levels of independence, maturity, and needs.

I would likely encourage you to do a 4 day plan for Beyond and LHTH too so that your younger kiddos' schedules match your olders. CTC and Rev2Rev are both 4 day programs. By doing Beyond and LHTH 4 days a week, you would spill over 9 weeks into the next school year to finish the guide, before heading into LHFHG and Bigger.
On the 5th day each week, you could only do the 3R's if desired or have your kiddos have a day off.

Just a few ideas!
Blessings,
Carrie