No problem at all doing your flights this way, when i helped someone last week check out pricing I noticed that the difference in fees was minimal -- the amount of cash you'll need to pay will be slightly more than if you book as one RT flight but not enough to make up for the extra miles involved with a RT ticket in my opinion -- I even used the silly miles-to cash ration to compare the difference in the cost of flights VS the cost of fees.
Here's the math from that exercise ...
If you book it as a RT flight you can do a Non-stop on Delta to Orlando the cost for this flight is
4322 AM + $141.05 taxes & fees
If you book separate One Way flights -- to Orlando -- on Air Canada for 1680 AM + $103.16 taxes and fees
back to Toronto -- on Air Canada again -- 1680 AM + $72.36 taxes and fees
Total for this is 3360 AM + $175.52 taxes & fees
Costs you less miles (962 --- if you use their mile-to-cash that works out to about $100/pp) but an extra $34.47