Yes you can but why is a mystery ? The Downloaded version is superior and cheaper since you will need at least the Online Deluxe version. The charitable donation has nothing to do with the choice of program you use.
To transfer the tax file from 2016 Downloaded program to the 2017 Online program
Last year's tax
data file (.tax files) can be transferred to Online Deluxe and
higher-tier versions.
1. Sign
in to TurboTax Online, if you haven't already done so.
2. Select Tools from the lower left corner.
3. In
the pop-up window, select Transfer
last year's TurboTax return from your computer.
4. Read
the warning and then click Continue (or Cancel to abort the transfer).
5. Browse to
where you saved your .tax2016 file
and select it.
6. Click Transfer Return and wait for your file to finish
uploading.
7. When
you see Transfer Complete,
click Continue to start working on your return.
https://ttlc.intuit.com/questions/1900883-transfer-last-year-s-return-into-turbotax-online