Obito isn't outspeeding Gamabunta and once Jiraiya entered SM and has Ma and Pa I find it unlikely for Obito to deal with frogs, Ma, Pa, Jiraiya and possibly clones.
There's also reverse summoning which would de-kamui him.
Distance is pretty much 5 meters. All he has to do is sink in the ground, reappear behind this guy and its over. SM? Jiraiya is never going to make it in Sage Mode at all nor is he going to summon Ma and Pa before he gets warped.
Reverse Summoning isn't saving him. Kamui dimension is not connected to this dimension nor are all ST Ninjutsu connected as stated by Kakashi, so the only way out/in is Obito's set of eyes.
His clones get destroyed by Giant Shuriken, Giant Kunai or in CQC by utilizing Mokuton Sashiki no Jutsu with Kamui. Mokuton Sashiki can also kill any frog Jiraiya summons.