Aweaver is steering you straight. Indoor/outdoor tight buffer is probably your best way to go and the prices on it have gotten down to normal (pvc jacket) levels. It also allows you to surpass the 50 ft rule after you enter the building. Therefore no splice to be done to transition to indoor rated. I'd disagree to favoring 50 micron over 62.5, but that's just because almost everything in my area has been done w/62.5 micron.

Breakout/fanout kits aren't hard to install and use. Even with ickypic fills. Just remember to ALWAYS clean them well with Hydrosol wipes (minimum of 5 good swipes down the strands), wipe them down with clean Kimwipes, and then wipe them down with a new Kimwipe that is dusted with baby powder. They usually slip right in with minimal effort.

MM good for short runs (<2000 ft) SM good for the longer. MM very good to GB speed but if MGB is desired use the SM. They will be paying out the nose for the active equipment anyhow, don't bottleneck them w/inadequate fiber.