Mercy had some great thoughts already!

We have done ETC workbooks before. They provide a basic phonics review, are short, and are fun. They take about only 5-10 minutes or so to do, so your dc can certainly continue with ETC along with Beyond's LA, as long as it doesn't prevent them from doing the skills in Beyond. Beyond's copywork and LA helped prepare my dc well for Bigger Hearts, so I'm glad your kiddos will be doing it now, as there are many good solid skills taught through them.

The way that spelling is done in the LA box helps prepare dc nicely for the dictation in BHFHG. The daily copywork has them writing longer lines of sentences or phrases, which prepares them nicely for the upped writing in BHFHG. Likewise, the grammar lessons each week lay the foundation for R & S English. The Storytime follow-ups are pretty important to do too. They helped our dc learn solid beginning skills to orally narrate well. I'm not sure if when you say you have been skipping LA if that means dc have not been doing the Storytime follow-ups, but I just wanted to mention them as they were awesome helps for our kiddos as they moved into the upped oral narration skills in BHFHG.

I am so sorry to hear of the difficult pregnancies - I've had my share of those too, and I know how that can add stress to life and to health in general. I hope you are feeling back to normal and healthy once again!
I am thinking your older dc could do Spelling List 2, from start to finish, not rushing or double-timing it. Your 6 yo should probably do Spelling List 1. It is not a big deal to do round table lessons with the different lists at the same time and will not add time to your day. Next year, your dc can finish out their spelling lists along with the LA plans for them at the start of BHFHG. Whenever they finish, the older 2 dc can do Dictation Level 2 in BHFHG, and your younger child can do Spelling List 2. For grammar, I would probably do 2 lessons a week instead of 1, working through the Day 5 plans in the guide doing 2 of those lessons each week, so you finish the grammar introduction prior to dc beginning R & S English 2 in BHFHG. I have a goal to have our dc copying the entire poem each week by the time they finish Beyond. This is a personal goal- not an HOD goal necessarily, but I have found it helps them be ready for the increased writing in BHFHG nicely. For your older duo for sure, that would be a good goal. For your younger child, perhaps less would be fine. HTH!
In Christ,
Julie