advice before starting

hi all, my LO is 7 months old and cannot go to sleep without feeding/being held. i haven’t slept more than 3 hours since they were born.

we have decided to sleep train but using the ferber method. they currently have a cold so we are waiting to start (cannot come soon enough) but i have a few questions.

1. checkin times. say we put them down and do the 3min, 5min and 8min and they go to sleep. if they wake do we start again from 3 mins or carry on to the 10 mins??

2. they are breastfed so i always assume they need milk during the night. they are quite good at not falling asleep on the breast but i typically give in and end up co sleeping with them. should i continue to breastfeed if they want it even though it’s probably just a comfort?