Can both heel spurs and plantar fasciitis get better over 6 months with stretching exercises and orthotic device?are they self-limiting?

Yes: This is often the main treatment used for plantar fasciitis and heel spurs. Other treatments are available if thus does not work. Sounds like you have a good doc treating you.

Heel spurs: As heel spurs are boney , without surgery they remain. However, with what i call aggressive conservative care plantar fasciitis / heel spur syndrome gets better about 99.5% of the time. As said , it sounds like your doc is going about this correctly

Yes: If you wear your orthotics, stretch and ice daily and refrain from walking barefoot, there is a great chance that your pain will eventually subside.