i had thought "banyan" wasnt necessarily a species ?
but a group inside Ficus ( i may be wrong)
from what ive seen, banyan and F. Religiosa look very similar.
i would think grafting would be fairly easy on all ficus.
i just tried mulberry+fig and also fig+ mulberry grafts
but, we just had a freeze, i might try again in spring.
all the mulberry+mulberry grafts and fig+fig grafts ive done have taken.
(all the figs were inside Carica)
but they seem to take readily.
personally, i like raising food plants
another thing to contemplate...
i dont know how sure they are about Buddha and the exact species of tree.
for all we know, it could have been F. Carica (ancient form, or parent?)
You could say -- "They believe it was a Ficus species similar to this..."
a lot of sales of indoor plants are referred to as "grafted Ginseng Ficus"
i had to read up on it,,,
quite interesting... talks about grafting too...
https://www.dallasbonsai.com/care-guides/ginseng-ficus.htmlpeople at the fig forum, can probably answer grafting and other questions
http://figs4funforum.arghchive.com/garden-web
http://forums.gardenweb.com/forums/fig