Should I just offer to assume the mortgage and not give anything to the existing owner, or would it be better to offer them something so they are not losing all of their equity as well as ruining their credit?

This lack of financing is also having a severe impact both on those consumers wishing to purchase a manufactured home, and on the existing manufactured homeowners who find their homes diminishing in value because subsequent buyers cannot find the financing to buy existing homes that are for sale.

Check posts about seller financing and tired landlords.Throwing in a lump sum on existing loans doesn't effect cash flow immediately it shortens the time to the payoff and reduces interest expenses, that are deducted from income.

Tell the existing tenant that you are renting out your side for "the current market rate" and that you are going to continue renting to them "under market" as they have been good tenants but if you catch a bunch of flack from the new tenant because they tell them how much they are paying... they will be looking at an increase on the next lease,  or in 30 days if they are on a month to month.  

Based on 1.5 million you could theoretically at 75% LTV pull out 1,125,000 max. 1,125,000 - existing 750 = 375,000 to be accessed.Now say that appraisals come in low at 425k each instead of 500k.

I do plan to flip a house here or there if a great deal presents itself, and use the money made from that to either pay off existing mortgages (unfortunately then having to pay capital gains) or purchase a few more rentals.

IF, FOR ANY REASON, SELLER (A) IS UNABLE TO MAKE THE TITLE INSURABLE OR CORRECT TITLE PROBLEMS OR (B) IS UNABLE TO OBTAIN TITLE INSURANCE FOR THE PROPERTY FROM A REPUTABLE TITLE INSURANCE COMPANY AT REGULAR RATES OR (C) DETERMINES IN ITS SOLE DISCRETION THAT IT IS UNABLE OR IT IS ECONOMICALLY NOT FEASIBLE TO CONVEY GOOD AND MARKETABLE TITLE TO THE PROPERTY INSURABLE BY A REPUTABLE TITLE INSURANCE COMPANY AT REGULAR RATES, AT THE CLOSING DATE, AND SUCH CLOSING DATE IS NOT EXTENDED OR OTHERWISE AMENDED IN THE SOLE AND ABSOLUTE DISCRETION OF SELLER AS SET FORTH ELSEWHERE IN THIS AGREEMENT, OR (D) DETERMINES, IN ITS SOLE DISCRETION TO DEEM THE AGREEMENT NULL AND VOID IF REQUIRED BY APPLICABLE LAW, AND/OR REQUIRED BY ANY EXISTING CONTRACT OR AGREEMENT BINDING UPON SELLER AND/OR THE PROPERTY, INCLUDING, WITHOUT LIMITATION, ANY AGREEMENTS WITH THE PRIOR OWNER OF THE PROPERTY, ANY MORTGAGE INSURER OR ANY MORTGAGE BROKER, THEN SELLER MAY CANCEL THE TRANSACTION CONTEMPLATED BY THIS AGREEMENT BY WRITTEN NOTICE TO THE OTHER PARTY AND THE ESCROW/CLOSING AGENT.

{Two years later they changed their minds and wanted to live in a freshly renovated unit - but that's another story].At the time we were renovating vacant units and both filling them with new tenants and moving existing tenants to free more units for renovation.  

My honest answer was I went to "Big Bank" because I have an existing relationship with them so they know me.

Maybe buying a condemned property and turning it into a parking lot or buy and existing one.