This isnt exact but if your gross monthly income is twice that of your current monthly debt on credit report plus your new housing expense you make enough to qualify (roughly). 

Now i have been tasked with helping my mom invest the money in her 401k account, I was wondering if there was a way to be able to take out 100% of the accounts balance to buy property with it .

Using credit cards/helocs could temporarily lower your credit score if they are maxed out (30% of your credit score is credit utilization), so keep that in mind. 

All of my LLCs have their own bank accounts, books, expenses, etc.But what else do i need to separate? 

As long as your credit score is decent and there's no bankruptcies or defaults or felonies in your b.g. then Hard Money is perfect for you to help you scale, especially if you want to buy low, rehab it, and then refi out at a much higher value.That would require a bridge loan with rehab and then refi into a DSCR 30 year loan. 

It all comes down to 50 or more years of no Inspections with Deferred Maintenance by the criminal HOA's which now have to be paid for in short time with Zero Money in the Reserve Accounts.

-- You will not find this level of service with a regular bank or credit union. 

I have a Home Depot account and I have my workers pickup material and they (HD) text me to confirm.

It's a tax deduction pure and simple, not a tax credit.

They will also get an appraisal done and run a credit and b.g. check.