بسم الله الرحمن الرحيم
(1) The first ten days of Dhul Hijjah carry lots of virtues. Allah has sworn by these ten nights in the Holy Quran. It is recorded in Hadith that praying during each night of these ten days is equal to worshiping in Shab-e-Qadr and fasting during each day of these ten days is equal to fasting of one year. And the rewards of good deeds are multiplied during these days. i.e. the value of good deeds increases during these ten days.
(2) Walimah is sunnah provided it does not carry extravagance, publicity and fame. As far as the matter of prevalent barat is concerned then one should avoid it to possible extent.
Allah knows Best!
Darul Uloom Deoband