This will not have any major impact on your ability to setup and contribute to a Solo 401k plan.

Also, maxed out cards are bad for your credit score, potentially impacting your future ability to obtain a loan(mortgage) on good terms.Consider the alternative- a 20% down payment with that sort of coin could land you a house which sells for $150k.

It may also impact you with non-traditional lenders, who usually have a net-worth requirement and take into consideration your assets and liabilities. 

Have you calculated your profit after the tax impact of cashing out your IRA?

Does anyone have enough experience in Real Estate investing to know the potential impacts of war on the market?

The house of course is being sold as is but for an environmental hazard, I didn't know if there were specific rules around that. 

What would the impact be if you have to evict a tenant (or two?)

That means they’ll have absolutely no impact on your FICO scores.When the mortgage inquiries age past 30 days they become fair game and will be seen by the FICO scoring system.

Several mitigation techniques can often significantly impact your costs.

Neither of those sites impact your credit score because they do a soft pull on your credit.Other than that, don't open up too many credit cards at once (maybe 2 cards total), because too much at once impacts your score in a few ways (hard inquiries, new trade lines, and age of credit history).Last, pay your bills on time...late payments really negatively impact your score.