At 12-13 months I did the same as I do now.
Morning milk on WU (when I say on WU it's more like 30min or more after WU. My LO wakes early so he plays in his cot a while then we go the bathroom for him to use the potty and eventually downstairs and I prep his milk - it all takes time). The morning milk is his big milk drink of the day (180ml, about 6oz) and given in a cup with straw (with me holding/helping).
Breakfast is around 1 hr later. Water in sippy.
morning snack and water
early lunch and water (pre nap, he was on 1 nap at 12 months and still is)
late lunch and water (after nap) - yes two lunches!
afternoon snack
dinner with sippy milk (about 1 - 2 oz of milk, he is always offered more than this but doesn't take)
pre BT sippy water
We just recently made dinner a bit later because I'm tweaking BT but right up to now last solids has been 5.15pm with 7pm BT. I found any later than this and he would have difficulty sleeping due to digestion, wind, needing a poo, etc
Like I say he has always been an early riser in the morning but having his last meal at 5.15 (and milk) didn't effect this at all. He also had a marvellous phase of sleeping 12-13 hrs at night so went something like 15 hours between one meal and the next.
I don't know how well your LO has taken to solids but at 12 months the aim is to get the calorie intake from solids rather than milk (of course they still need milk too though) and become a more grown up eater like an older child or adult, we don't wake at night for feeds, we take all our calories during the day. LOs tend to need snacks between meals to keep them going as their tummies are too small to hold the amount of solids needed to get all their calories. When you remove the day milks replace with a healthy snack and water in a sippy (or your choice, open cup, straw cup, doidy cup).
Many LOs don't eat a lot in that last solids meal of the day, they're more likely to eat larger portions for breakfast and lunch, less towards the evening and then really once they go to bed shouldn't need any more food until morning.
If you found that your LO wanted more BT milk than usual (after replacing day milks with snacks) then I would take that as an indication to increase the meals or snacks in the day. Generally you'd offer food until they are full any way.
A lot of people keep the BT bottle. I suppose it's fear of LO being hungry, fear of 'ruining' a lovely BT routine and ending up with a crying LO at BT - no one wants those things. I don't know if it is harder for LO later on, maybe harder for you? Half the time these things we are scared of moving on are harder for us than our LOs. I wouldn't feel bad about keeping a BT bottle, it is so common.
My reason for removing it (bringing the milk to dinner time with solids) was personal choice, based on the guidelines to get rid of the bottles but also my own feelings.
Our BT routine was brush teeth, bath, nappy, pjs, then into bedroom, milk and snuggle, a song and cuddle then into his bed (awake) and leave. It worked, it was lovely. I didn't really want it to change but I felt it had to because I've heard (seen pics etc) of 2yr olds with cavities and tooth loss

So I knew I had to change the routine and give the milk before brushing teeth and I thought if I am disturbing our BT routine anyway I may as well also get rid of the bottle. I was scared of the change but in all honesty my LO never noticed the difference. For a short while I did the milk at dinner and still took a bottle of milk up to bed with us in case he wouldn't settle without. Then after a short while I had the courage to just take a sippy of water in case he was thirsty. For a while he took a little, now he doesn't take any unless he has a cold.
We still had our cuddle and song and he continued to go to sleep as normal. I was really glad in the end that I'd had the courage to try it and ditch the bottle. This all happened when he was 12 months, the BT bottle was gone before 13 months.
The morning bottle I kept another month or two. I did try to move it to a sippy cup but he was really annoyed at that. I spent a bit of time in the day teaching him to use a straw and also snipped his bottle teats so they were a rapid flow and he drank them sitting upright (still cuddling on me) then one day replaced the morning bottle with a straw. I had a bottle on stand-by in case he was unhappy but he was fine and from then on never had another bottle.
Maybe our story helps you decide what to do but in the end it's your choice.
xx