Hello Marlon,

in real world edge routers R2 and R3 will peer with two different ISP routers for redundancy and fault tolerance.

iBGP session is recommended and necessary if the edge routers are simply generating a default route in OSPF telling they are exit points from OSPF domain.

Again in real world this choice of simply injecting a default route usually pays avoiding to inject BGP routes into OSPFdatabase.

OSPF provides useful tools for advertising a default route only under specific conditions by using

router ospf 10

default-information originate route-map check_BGP type 1

where you can check that a default route is sent to you on an eBGP session.

in any case either for the default route or for injecting BGP routes you should use O E1 routes because you have two exit points (ASBR)

going back to your question, if you have the iBGP session you should check BGP next-hop

access-list 11 permit host ebgp-address

route-map BGPtoOSPF permit 10

match ip next-hop 11

! other matches here

this to avoid that after one eBGP session fails the router tries to redistribute iBGP routes into OSPF

note: this is not necessary unless you have enabled redistribute-internal under router bgp process

Hope to help

Giuseppe