We have used 10 speed 26-39-53 front rings with Ultegra 10 speed front derailleur. Worked just as well as the 30 tooth granny except there was of course a bigger change in cadence when we dropped into it. We did use a chain catcher which I recommend regardless of granny used. 26/34=.7647 and 26/32=.8125 so you might be able to go with a 32 big cog if that works better for you.

If it were me I would only change shifters and cassette and see how it shifts before changing more. I do my own work so labor is free.