Unrelated to your concerns, I would suggest a screen or plumbing vent cap to keep rodents from dropping in through the vent. Most don't realize that this is a thing that happens.
Loose-fill insulation is not great in vertical applications. If you can afford it get spray foam. Otherwise you’re probably best off with basic fiberglass batts.
My understanding of this (just worked through it with my wife) is that you will not take a tax hit on the disbursement when you take it but you will get hit with capitol gains taxes on it’s growth from inception of your contributions.
When you take it out, it has already been taxed but it will still count as income for your tax planning purposes in the year you receive it - hopefully you’re in a lower tax bracket when this occurs. It is not a taxable income (though it counts as an income and increases your tax bracket accordingly) but it’s growth since contribution will cost you at your current tax bracket as you take it.
You are wise to be concerned but I think you will not design an “enclosure” that will prevent further damage if it is inside a wood frame house. There is a house near me that burned down because of a single power brick for a tool in the garage.
Your better approach would be to make it so that power delivery is monitored and regulated automatically. That or manually just unplug after charging.
Thermal runaway happens on over-discharge or overcharge of the battery pack. Each pack has smart circuits to regulate this but they are designed at scale with a squinty eye at overall product cost…cheapest circuit available gets used even by well-known manufacturers.
Place power draw monitoring on the delivery circuit and when the draw lowers to maintenance level (batteries have recharged) have the power delivery automatically cut off. This can all be automated with freely available smart home products. You can even get some temperature sensors to monitor for overheat conditions during charging.
I wouldn’t be overly concerned that the concrete cracked…it does that sometimes. Be concerned if you have heaving/unevenness in the support of your home. As others have said - contact a professional. I would suggest an engineer, not a foundation repair salesman…you get where I’m going with that - the foundation company will always suggest large-scale repairs. An engineer that has no financial dog in the fight will cost a bit but will give an hones opinion.
