Hi, I have checked the tree and the skulls images. I can make that within the poly limit and can unwrap the UV's as you have mentioned, so the artist can texture easily. I am a professional game designer and very good at low poly high detailed models.
I am charging $125 each model. Please direct message me so we can discuss the details.
You can trust me with quality work and timely delivery, please do check my portfolio and profile reviews given by other employers.
Portfolio:
https://www.freelancer.com/u/aki230990.html
I am looking forward to hear from you.
Regards,
Amit