Hi there,
I read your project and it is interesting. I have +15 years experience in general programming and +10 years in trading software development in almost any commercial language available. I am an IT engineer and I work exclusive with Financial projects.
All Trading Bots are composed of three components:
1. Reading of quotes.
2. Determination of Buy, Sell, Close, signals and/or position update (SL/TP).
3. Execution of trades.
These three components are the core of your project, all other features you may include in it are only enhancers of these three. So, once we have this general structure, you then can build literally any trading strategy you want. So, your project is quite simple and straightforward, a little large but still simple. If you want I may also include the UML structure of your project at no additional cost, which will show you how the components interact with each other internally, among other details.
Another consideration you may also consider is the language, as you are going to host this trading bot in an Ubuntu system, I'd highly recommend you to implement it in Java. In Java, you can execute your trading bot in any OS, not to mention that it is a very solid language which will give to your solution the stability it needs to run 24/7.
I placed 10 days on my bid. 8 days to deliver your project and 2 more to handle any adjustment or modification you want to make. I also added a budget of ~$500USD as you suggested.
Regards,
Eng. John P.