Is it the new tank that has the chip on, or the old one? I can't quite work that out. I assume it's the one you currently have. If it's the one you currently have, and it hasn't gone ping yet, then it's probably not going to.
If it's the new one, and if you're worried about the chip affecting the integrity of the tank, I'd set the tank down outside on some polystyrene or grass, then test-fill it with water. That way it doesn't matter (as much) if it goes ping as it would do if it did that in the house! If it holds water ok for say 24h, drain it down, and then proceed pretty much exactly as you have described:
-Wash sand
-Remove old ornaments
-Remove fish to large bucket filled with tank water
-Insert existing filter into bucket to keep it ticking over while you do everything else that needs doing (switch it on, obviously!)
-Drain old tank
-Remove substrate and plants
-Save plants
-Remove old tank
-Put new tank in place
-Add sand
-Replant
-Add ornaments
-Add dechlor sufficient for 1.5x volume of new tank
-Fill with tap water (don't worry about bringing over the 25% from your current tank, it won't make any difference)
-Move filter over to new tank, switch on filter, heater etc.
-Transfer fish
-Clean up!
99% of your bacteria live in the filter media anyway, and only a negligible amount in the gravel substrate. As long as you're not adding any more fish when you do the tank-change, your filter will handle the new tank just fine. Give it a week or so for everything to settle down and be a bit more regular with your water tests than you might normally do (maybe daily for the first couple of days, just to be paranoid
) It'll all be fine.
Enjoy your new tank, and good luck!