You could however roll over your 403 and 457 into the Solo and start make investments.  

If its a shingled roof ask whether it can be a rollover roof (just adding a 2nd layer of shingles) to reduce the cost.

Rollover from a qualified retirement account and contributions. 

Backup to this would be a Self-Directed IRA - though because the contribution limit is so low, (7K 2024) you'd need to do a direct rollover for this to make sense.  2. 

Then General Partners can share in profits.It’s not unusual for syndications to roll over a balance right into the sale of the property.

If I pay a buyers agent fee and sellers agent fee (to me) I can LEGALLY collect a succuss fee of selling my property in a 1031 and roll over the funds into the next investment.Has anyone done this before and did it work out for your investment plan or hinder your growth.

I want to rollover my IRA into a solo 401k (I'm self employed) and borrow against the 401k for real estate ventures.

Rolling over your former employer 401k to an SDIRA or Solo 401k is not a taxable event as it's a direct rollover. 

You MUST claim in it 2018...even it at the very minimum it get's carried over as a roll over non-operating loss in 2019. 

Your "workplace investments" are likely not available until the employer becomes a past employer so a rollover from those accounts are probably not part of the conversation.  2.