LHTH is such a good start to homeschooling.
My dc already knew their letters and most of their letter sounds when doing LHTH, but I thought it was still such a good way to teach them to listen well to readings, learn to answer the questions well after the Bible readings, follow directions for art projects, listen and discuss devotionals, and work on fine motor skills of color/cut/paste/simple writing. They actually were both reading very well by the time they started LHFHG too, but we still did our phonics program to be sure there were no gaps. I think laying that foundation well for future learning is super important. We've found that by doing this, our dc are thriving with their guides and able to tackle everything in them, even the more difficult assignments in the upper guides.
Though I did LHFHG with my early reader and writer when he was 4 1/2 yo half-speed, he's had to grow into each of the subsequent guides at half-speed. It's actually gone very well because I've been willing to go half-speed, but I'm not rushing with my youngest through LHTH. (Plus, he's my "baby", my last little pumpkin that I can savor LHTH with
).
Do you have the more difficult Bible, "The New Bible in Pictures for Little Eyes"? That Bible really taught my dc to listen and answer questions, and was good (and necessary) prep for being able to listen and answer questions from the LHFHG Thorton Burgess books used for Storytime.
Do you have the "My ABC Bible Verses" devotional? That is a devotional that is more difficult and good prep for the devotionals to come in LHFHG on up. You could easily do both devotionals. They are different from one another, and both encourage a love for the Lord, as well as a steady diet of improving reading comprehension.
I think it is important to do the Fingerplays in prep for the Rhymes in motion in LHFHG, the simple art in prep for the harder history-focused art in LHFHG, the simpler books and comprehension questions in prep for the harder books with fewer pictures and a more classical CM sounding feel to them in LHFHG, etc. Plus, it's just plain fun.
I love the pp's ideas of adding "Do It Carefully/Finding the Answer" as well as "A Reason for Handwriting K" or "Italic A" to your sweetie's day. If you do start the Earlybird math, it would be worth getting (IMO) the LHFHG guide for the hands-on math lessons for it. They are wonderful. We've found them to build a great foundation for the later, much more harder math to come in Singapore.
You will know best here, but I'd get the harder BIble, do both devotionals, do all of the boxes as training for LHFHG, add "Do It Carefully'/Finding the Answers" and a handwriting program, consider starting the EB Math and hands-on plans, and keep doing your phonics - before stopping LHTH and starting LHFHG.
I'd even consider doubling it up doing 2 entire pages plans a day in LHTH before stopping LHTH and starting LHFHG. I just think LHTH makes LHFHG a success, and it gives dc a real sense of joy for homeschooling. You will know best here, but I hope something here helps as you think through it!
In Christ,
Julie