8 b TXS0108E level translator - OK with sensors?

I never used that level converter but judging from the datasheet I would say that it should work in the given environment. I assume you use the chips directly (BMP280 and TSL2561) and not some breakout board (which often include the level converters).

Apparently, the simpler alternative - the 2 channels one that I have, cant work with two sensors on I2C,

That probably means that it isn't a bi-directional type.