1-The idea in itself is good and there is no objection to it since Islam encourages caring for animals. The Prophet mentioned in a hadith the reward earned by the man who gave a drink of water to a dog. He said, "A man felt very thirsty while walking down a road. He came across a well, climbed down inside it and drank. When he climbed out, he found a panting dog eating the mud out of thirst.

 

The man said, "This dog is as thirsty as I was."

So he climbed down the well again, filled his shoe with water, and gave the dog to drink. Allah was satisfied and accepted this deed from him and forgave him his sins.

 

They [the Companions] asked, "O Messenger of Allah! Are we rewarded on account of animals?"

He replied, "There is a reward on account of every living creature" [Bukhari].

 

The Prophet said, "A woman was tortured [after her death] because she had imprisoned a cat until it died. She entered Hell-fire on account of this—she neither gave it food or water, nor did she release it to eat from the vermin of the earth" [Bukhari and Muslim].

 

2-Donations must be spent on stray animals except if there is a clause agreed upon by the donors and project administrators or stated in the bylaws of the project concerning paying the project administrators wages or monetary remunerations in return for devoting their time and effort in working for the project.

 

3- The land allocated for the project is subject to supply and demand. You can participate with it in the project and quote the price that suits you regardless of its purchase price. The Prophet said, "Let the people benefit through one another" [Muslim]. This is especially so since the project is partly a profit based investment as mentioned in the question. However, good manners dictate that one must not neglect cooperation upon piety, being mindful of Allah, and refraining from exceeding the proper bounds.

The above answers the question and Allah the Almighty knows best.