Lots buildable? 这些LOTs可以建房吗？

I am looking to buy a property with two additional lots in a nearby county, I need to determine whether those two lots are buildable. While I have contacted the county for their opinion, I came across the deeds of the previous transactions. Basically at one point in the past transactions, the deeds state that "not to erect anything other than a private garage", however, the current deed did not say anything like that.

So my question is whether those restrictions are still valid, and maybe a followup question is whether such restrictions can be removed by hiring a lawyer, and how likely is it to get the court approval.

Thank you in advance.

大致图， 黄色的是附加的LOTS。（sorry, taking forever to upload the pictures, give up now)