@Chris Virgil-Stone, as long as the TIC interest you take in the new property is equal to or greater than the dollar amount of your net sale you will defer all tax.The only way your scenario works is if the taxpayer for the old property is the same as the taxpayer for the new property. 

Ideally you generate 25% equity during the rehab, which usually does not happen (at least not for me, I average about 10%) - unless you defer some of the needed updates to the future.

To me it is not fun to pay taxes so I want to avoid or defer paying taxes as much as possible.

Solo 401k allow you to have two buckets of money: traditional pre-tax which grows tax deferred and taxed at distribution and post-tax Roth which is taxed upfront but grows tax-free and qualified distributions are tax free.Hope this helps!

Is there anything that can be done about a deferred loan modification?

You can invest in stocks tax deferred which is a great benefit.

Just know that you have to pay that balance in full or you'll be stuck paying all of the deferred interest at the end of the term.I'm not aware of any good cards that offer points AND 0% APR.

It is easier for them to justify full price with a specific budget to fix deferred maintenance. 

My agent brought it to me and we negotiated hard because there was signifiant deferred maintenance.

My agent brought it to me and we negotiated hard because there was signifiant deferred maintenance.