Got it Lava! Back to your original topic!
That is, are there tax consequences of moving money from IRA to solo 401-K.
The answer is, Possibly! Would not know this if it had not bit me. And how it applies to your more-complex diabolical plan I know not. Leaving that to your bean counter.
The wrinkle comes in because you are of age to require an RMD. I had thunk that 401-k was on equal footing with all other types of deferred accounts but it is not! That is, it has its OWN RMD requirement! Same as the rest, but you cannot take it over there and expect it to count. So if you were expected to take 5K out of the 401k and did not, guess what! I’m here from the government and I’m here to help you. Custodian expected me to not only take it but to have tax withheld!
Anyway, in my simpler situation, it seems easy enough to avoid. Simply roll over most of that 401k to TIRA so its value is trivial on 31 December. Voila!