We'd really appreciate it if you experienced investors can take a look at a few of the terms we've been playing around with and give us feedback letting us know how we can sweeten the deal for both the equity partner and ourselves.

Could I withdraw my offer (not currently accepted) and add some form of condition saying I may get a mortgage directly through this bank (to help sweeten the deal)? 

I found the deal on the MLS, and with 4 other offers on the table, as a new real estate agent, I waived my commission (with my brokers' approval) in order to sweeten the deal by 3% without having to worry about appraisal issues.

In order to “sweeten the pot” I am considering offering the property to him at $70,000 cash or $80,000 and I carry the mortgage at a below market interest.

In our case, my wife is a licensed agent and we have bought two investment properties so far with her as our buyers agent and she has received the agent commission from the sellers which has sweetened our deals a bit and we love the control we have over the purchase.

We want to sweeten the pot so that it is a good move for the owner as well.

If you find any company who may be willing to do such a deal, I'll be willing to go in with you and bring my properties on to the deal to sweeten ti for them! 

How can we sweeten the deal? 

The seller  wants all the terms in their favor which is understandable, but remove the balloon or get a much better deal on terms such as..interest, down payment, or something to sweeten the deal.

you can sweeten the deal up with whatever cash amount makes sense here. unless, like Jay said, you're just trying to wholesale this to somebody else.