本人二月遊北海道4D3N and 8D7N in Tokyo

Sorry that you'll miss both events but a 2 days trip in Sapporo (扎幌) and 1 day trip in Otaru( 小樽) will not disappoint you. For the remaining 1D1N, you can stay one night in 登別, say http://www.takimotokan.co.jp/ (able to reserve online), where free shuttle buses are available for return trip from and to the Sapporo Bus Terminal (Near JR Sapporo Station) http://www.takimotokan.co.jp/access/index.html of schedule and station map in http://www.takimotokan.co.jp/access/access1b.html (best be arranged when booking).
For the 2 days trip in Sapporo, you can consult the tourist centre in the JR Sapporo Station during their office hour http://www.welcome.city.sapporo.jp/access/annai1.html . There are many standard routes suggested to you and travelling passes sold. Also, you can visit their offical site for reference first http://www.welcome.city.sapporo.jp/.

Besides the two festivals you asked, there'll be other festivals near Sapporo during your visit:
円山動物園、雪まつり 2010年2月1-11日 http://www.welcome.city.sapporo.jp/feature/07_02/detail.html

You can consult the information centre for further information.

For Otaru, most places are within walkable distance, just find a travel map and you can enjoy the day trip!

Yes, you will certainly miss the Otaru snow gleaming(小樽雪光之路) as it will begins from 5 Feb, they will only prepare it on that day and you can see nothing until that night.

However, you can see the ice work in Sapporo since the people will prepare it a few days before the snow festival. But you cannot see the show prepared for the snow festival.

如果你日本同英文都麻麻地, 都係跟團去啦.

你D英文似乎好唔掂喎，大約只有小學程度，全無tense {時態}，一時用過去式 {past tense}，一時用現在式 {present tense}， 但全不見有 future tense。

#有批評才有進步。