Just an all round person that can do cabinet installs and other finish carpentry and maybe light plumbing and electrical? 

It is called an installment sale.Here is an example: if the house sells for $200,000 and the seller's cost basis is $100,000, the total gain is $100,000.  

Since you are going to have an electrician do a substantial amount of work after the demo to install all the new circuits, I consider this part and parcel of the rest of the work they will be doing.

Possibly added value with kitchen installed downstairs...

If your goal is cash flow (in my opinion) you're better off trying to buy with owner financing (contract for deed - land contract, installment sale, mortgage wrap, promissory note with a first lien holder position on the trust deed for the seller (if they own it free and clear), or sub2.

I wasn't sure if I can raise the rent a bit to cover myself for the winters or try to zone by ripping out the boiler and installing central ac and heat in basement for unit 1 and ac and heat in attic for unit 2.

Engineered hw is easier to install and it is cheaper, but would the buyer ask about it or can we put it as "hardwood floor" to the MLS ad?

Mainly need someone to install windows.

Hi guys,My tenants has been living in the house for over 4 years now wants to upgrade the carpets, install new blinds and repaint a few rooms.She offered to pay for all of it as there is technically no reason to change all of this at this time.

Appliances are cheap and easy to install.