Two Reformed views; Amyraut: unfallen man would have lived forever, but only an earthly life
To make my own view on this clearer: I find two opinions in the Reformed schools about the unending life unfallen man would have had.
Some hold that if the first man had remained in obedience to God, according to the covenant of nature God made with him, he would indeed have lived forever, but only with an earthly, animal life that would never have been changed into a heavenly and glorious one. This is what Moses Amyraut teaches in his Theses on the Three Divine Covenants.
Latin
XXXII. Ut distinctius tamen aperiam quis sit meus ea de re sensus. Observo in Scholis Reformatis, circa perpetuo futuram hominis integri vitam, duas esse sententias. Etenim nonnulli sunt qui censent primum hominem, si juxta naturae foedus cum ipso a Deo contractum, in obsequio Dei permansisset, perpetuo quidem victurum fuisse, sed solummodo vita terrena atque animali, quae in caelestem atque gloriosam nunquam commutanda fuisset. Quae est doctrina Mosis Amyraldi Thesibus de tribus foederibus divinis.