The ladies are wonderful about helping talk through options aren't they!

As to your 6 year old and 4.5 year old, I would slide both into LHFG. Again, since your daughter is the one who is 4.5, you have a better shot at combining her with your 6 year old, since girl's fine motor and listening skills often develop more quickly than boys. With both of those programs, you will still be done before lunch or shortly thereafter.

For your littlest one, you could definitely wait to start LHTH, or since I feel your heart saying you feel guilty and want that little one to have something special... you could just do LHTH as time allows. I scheduled 20-30 min. a day with my toddler and when I could I did part of LHTH or all of it. It took us several years to go through the guide, but my little one felt special, and I felt great about having something special to do with my little one (that didn't require any prep. or planning).

Blessings,
Carrie