2 months is not ideal to ween but not so bad either...if they are not used to taking s bottle then I would stick to hay, graze and small amount of quality grain...Loose mineral and fresh pan of water...I would also have a fecal done by the vet to see what if any worms are present..be sure to ask for a cocci check as well..
when giving new foods..you need to give it slowly...a little at a time and increase a small amount until they are used to it...too much too fast can upset the tummy..Personally I would not give the apples...a small slice or two is fine as a treat now and again but you want them eating hay and graze mostly...
If your buck is not fixed he can and will breed his sister...so wethering him would be a very good idea, and soon : )