I was leaning towards making an offer with the adjustments in the offer and trying to explain why I was deducting from the beginning and hoping that would help seal the deal.

I haven't found it to be any easier even when the grout is sealed, in fact the sealer doesn't seem to make any difference.

Well apparently, the title company forgot to seal the envelope.

Hello @Israel Seales and welcome to Bigger Pockets.

Some problems can be fixed along the way, but after close of escrow you can never renegotiate the purchase price and you can never move the property to a better location ... your fate as an investor (good or bad) is to a large degree sealed the day you close escrow, so choose wisely, negotiate hard, and be disciplined.

Same with seal coating the parking lot, etc.

This isn't needed for sealing, but it helps you get the nut down tighter, and also helps you get it apart again later if that is ever needed.Shutoff valves are available in various combinations of straight, right-angle, and even double outlets. 

--seal the envelope, or just fold the flap?

There's one installer in our area known for cheap prices - well, he pays his install crews about half the going rate, so he gets the drunkest guys who can't get work from anyone else, and they just slap those things in with hardly any caulk or weather sealing.

I'm a red seal roofer by trade and it sounds to me like you may have a double vapor barrier happening.