Seller does not want to share tax returns or bank statements because they are combined with his other park. Common issue or red flag?

I have a seller that agreed to seller finance that is bulking a little. I have provided proof of funds and a professional bio since I do not currently own parks. He stated " looking for financial evidence that would support giving a $900k loan." My response is that the park is the collateral and that the financial performance of the park should provide confidence. Any thoughts about what else could help?

Here’s a dumb one: how do you guys plant new grass in a park you manage remotely, and where every resident is on individually metered water (and, therefore, doesn’t want you using their water, and isn’t interested in helping you by watering the seed/sod)? And what about when grass needs to be grown in a spot that’s not really near any water spigot?

How concerned should I be with small cramped lots? All of the homes are old but seem to be in ok condition now. However, when they reach the end of their life span, replacing them would mean a costly shuffle of the park layout to get newer homes in.

Contract for the 14 pad park has been sent, waiting on signature currently!