Hi Janus,
I am a Florida Realtor. Just to make sure I understand correctly, you are offering 75k for 2 homes as opposed to 150k for all 4 homes?
If so, essentially you are offering the sellers exact asking price as they are wanting to sell each home at $37,500. It will be up to the sellers to determine if they want to split up their 4 homes or Just find another buyer to purchase them all. (Usually, their decision will be based on the average days similar properties have been sitting on the market, average sale prices, and how quickly they want to sell)
Realtors typically negotiate purchase price through a comparable market analysis. You will need to look up every home that sold in that area that had similar features as your home. For realtors, this information is in the mls but I think Zillow also now offers this information.
Choosing the right comparable homes are where you can get creative with negotiations and be able to convince the sellers why they should accept your offer. For example, If The seller is asking $37,500 for a 2bed 2bath but you found a 3bed 2bath In the same neighborhood, same upgrades, same features, etc that sold for only $38k, then you have every right to convince them their home isn’t worth $37,500 because your home is missing an entire bedroom and it’s not nearly as upgraded, etc. as the 3bed 2bath home.
But, this is a dance so you don’t want to offensive to the sellers if you really do want the property.
At the end of the day, a home is truly worth the price that a buyer and seller both agree upon.
For closing costs, in Florida the buyer usually pays the closing costs one way or another. So, in the event the sellers accept your offer for 75k, they are actually agreeing to sell their homes much less than 75k as the closing costs will be subtracted from the actual purchase price.
Oh and I recommend to always, always get an inspection! Whenever an inspection comes back, you can always re-negotiate based on what repairs are needing to be fixed.
I hope this helps alittle and good luck!!