> Then would you recommend I try with an F84 (that also
> says absolute max of  7.5V in the datasheet) which I
> happen to have on hand ?

No. You're too close to the edge. It would be much better
to give the PIC the 5V it should have. It will take just a
zener and a resistor. Either that or look for a PIC with
"Stunt" written on it

Are the transistors low-side ? ie, are their emitters to 0V
and their collectors to the LEDs ? If so then a 5V PIC o/p
will drive them on just as hard as at 7.3V, you'll not see
any difference in LED brightness

To be honest, I'd be looking for a more stable supply for the
LEDs too. How are they arranged ? 2 or 3 in series or just
one per transistor ? How about resistors ?

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