100% Lacto would run into some issues IMHO. Usually guys go with a sour mash or souring of the wort by pitching lacto, but then pitch Sacc when it gets to the point of being sour enough (days, not weeks, typically with this approach). You are blending, so you may be able to save that batch for blending more in the future, if it gets a bit too strong on the sour note. But sour is relative, just like hoppiness, I guess. Some guys can't get enough of that sour - I prefer a bit of sour and mostly like the funk. YMMV, of course.