One UART TTL input, GPS, 115200, 10HZ updates, NMEA, the data is sent to the arduino at a rate 10 times per second so the average baud rate is 32000bps.
A little confusing as you are using baudrate to define something other then what it measures. A baud rate is a fixed clocking speed that both sides of a comm link agree to use to clock individual bits onto the com link and does not change. Character rate is a variable rate that can be any value up to a maximum rate possible that can be supported by the baudrate being used. So at a 115200 baud rate, a link can support a character rate to a maximum of 11,520 characters a second (divide by 10 because, 8 bit character + one stop bit + one start bit). However that same 1152000 baud rate link can certainly be used to send a one character message only every one second, so the link would be working at an effective rate of one character a second, even though the bits in that single character are clocking at 1152000 bits per second rate.
So when you say a device like a GPS will be sending a message at a 10hz rate, it doesn't give us a complete picture of the character rate as you don't state how many characters are going to be sent every 10hz, so an effective character rate per second can't be determined. If the GPS message can be of variable character lengths then it's even more difficult to state the effective character rate, only a possible maximum character rate based on the longest possible message.
Baud rate is essential to know as it is used to configure the AVR serial hardware to run at the correct speed you require to support the comm link. Effective character rate is important to know so that one can determine what software support will be required to handle the message traffic from the link, such as possible arrays of a specific length to use to 'buffer' a complete message, and the amount of time your program will have to possibly parse the messages and take action based on the content in the messages.
So your table:
So that such a config could exist:
Data IN: 115200, NMEA, 10HZ
Data OUT1: 38400, NMEA, 10HZ
DATA OUT2: 14400, NMEA, 5HZ
DATA OUT3: 9600, NMEA, 2HZ
Needs at least one other data value added to each link, what is the maximum number of characters that can happen every xxHz message cycle?
Also do you see a possible fatal problem with your defined links? If you can receive new messages into the arduino at up to 10 messages per second but have to limit sending them out as slow as 2 messages per second then your input stream will certainly be coming in faster then you can output the messages, so input stream will have to be buffered and there is limited SRAM memory to support that and I think that sooner or later you will 'overflow' the input buffered stream and lose information?
Lefty