I also have such concern before but when my boy (also 2 1/2 months) was hungry, he eats anything no matter it is my nipple or it is the bottle. He can also drinks milk with any bottle no matter it is pegion, avent or chicco. So there should be no problem once the baby is hungry.
i had similar problem b4... i bf for 4 months and then one day i started to "force" my bb to take bottle. she kept crying and i kept forcing... this went on for about a week (each day slightly better) and then she's perfectly fine w/ bottle.
I think I am the lucky one then!! The way I trained him up was putting 2 ozs breast milk into Avent then let him finish first. And increase the milk one day after. I am not sure if it helps.
My bb struggled with the bottle problem at her 3 months old. That took me almost 2 weeks time to find out what's wrong with her, coz she was trained to use bottle since 4 weeks age but suddenly refused the bottle only want direct feed.
But then I changed Avent teats to NUK! She was fine with NUK bottle now!
when i first started to "force", i still kept some breastfeeding and only forced about 3 times a day (when feed by bottle, i only put formula inside bottle)...