Hi!
First For Aman Khalid. My project relates to high speed sampling application, so I use 24MHz crystal and I intentionly (ofcourse after doing some calculation) choose 300bps so that this low baud rate will not disturb my hardware performance.
Also for point you have given. I already have done all these steps plus few additional steps.
And for all others, I have PIII 733Mhz, and PIV 1500Mhz. And both gives 300bps.

The reason I ask this question is that I have been working on this project for long time maybe month or 2 and I was tired and out of money to increase hardware and complexity so I have asked whether 1 MCU have enough fanout or not. And how long it can communicate. So to finish my project quickly.
I think erik has given the answer which I need. So I will be happy, If any one give me any constructive Idea instead telling me to change the center piller of the building(my project).