Should I use the future tense or subjunctive here?

Should I use the future tense or subjunctive here?
 

Your sentence is correct. :thumbsup:

Subjunctive could be used for the question though:
- ¿Creen ustedes (Uds.) que encuentren vivo a Roberto?
- Sí, yo creo que lo encontrarán vivo.
(I used "yo" because, if the question is addressed to many people, an emphasis on my individual opinion could be good.) :)

¿creen que encontrarán vivo...? / ¿creen que encuentren vivo...?

Both are OK. The first one is more common because it takes side for them finding Roberto alive.

creo que será rescatado vivo | creo que no será rescatado vivo / no creo que sea rescatado vivo

I'd rather say:

creo que lo rescatarán vivo / creo que lo van a rescatar vivo
no creo que lo rescaten vivo

For the answer, indicative is used when the notion is in our minds and subjunctive is used when the notion is not in our minds.

There's no case here of subjunctive having to do with probability. In fact, of all the uses of Spanish subjunctive only a rather small fraction have to do with probability.

Thank you for sus respuestas! :) Could you tell me a bit more about the rules that dictate when to use the future or the subjunctive in a sentence?