I am a first-year beek. I have two top bar hives from packages installed 4/14 and one was booming (24 drawn bars) so I decided to do a walk away split on it a day and a half ago (6/25). I made an 8-bar TBH nuc and put a robber screen on it before doing the split...hoping the screen would cause the nuc bees to re-orient. I put one full bar each of capped (emerging) brood, pollen/honey & capped honey in with a new half drawn comb of eggs...all with bees on them....with I two empty bars next to the front entrance and two at the rear. I brushed (can't shake top bars in this heat) another bar of bees from a bar of brood (some capped and some not) into the nuc and closed it up. The nuc is about 4 ft. away from the parent hive and facing the same direction, but 2 ft lower. I live in the city and do not have many options for its placement. I am feeding the nuc 1:1 syrup.

Unfortunately, I had to leave to go to a meeting and could not observe what happened that evening, but yesterday I spent a fair amount of time observing and there were hardly any bees coming out (less than 50 for sure) and NONE going back in! I am now wondering:
---Did I put enough bees in the nuc?
---Did ALL the bees go back to the parent while I was away?
---Can/should I brush more bees from the parent into the nuc? This would have to be done TODAY because we are expecting 3-4 days of 100+ degree days starting tomorrow and I don't want risk breaking combs off.
---Should I just put the bars back in the parent and try again later...after I get more guidance from you experienced beeks? If so, what should I do different on the next attempt?

Thanks in advance for your much appreciated help! I don't know what I would do without help/advice from this forum!